MicroMod Environmental Function Board Hookup Guide a learn.sparkfun.com tutorial

Available online at: http://sfe.io/t2001

Introduction

The SparkFun MicroMod Environmental Function Board adds additional sensing options to the MicroMod Processor Boards. This function board includes three sensors to monitor air quality (SGP40), humidity & temperature (SHTC3), and CO₂ concentrations (STC31) in your indoor environment. To make it even easier to use, all communication is over the MicroMod's I²C bus! In this tutorial, we will go over how to connect the board and read the sensors.

added to your cart!

SparkFun MicroMod Environmental Function Board

In stock SEN-18632

The MicroMod Environmental Function Board includes three sensors to monitor air quality, humidity / temperature, & CO2 concen…

$149.95

FavoritedFavorite1

Wish List

Required Materials

To follow along with this tutorial, you will need the following materials at a minimum. You may not need everything though depending on what you have. Add it to your cart, read through the guide, and adjust the cart as necessary.

added to your cart!

SparkFun MicroMod Environmental Function Board

In stock SEN-18632

The MicroMod Environmental Function Board includes three sensors to monitor air quality, humidity / temperature, & CO2 concen…

$149.95

FavoritedFavorite1

Wish List

added to your cart!

SparkFun MicroMod Main Board - Single

In stock DEV-18575

The MicroMod Main Board is a specialized carrier board that allows you to interface a MicroMod Processor Board with a single …

$14.95

FavoritedFavorite1

Wish List

added to your cart!

Reversible USB A to C Cable - 2m

In stock CAB-15424

These 2m cables have minor modifications that allow them to be be plugged into their ports regardless of orientation on the U…

$7.95

FavoritedFavorite4

Wish List

added to your cart!

Pocket Screwdriver Set

In stock TOL-12891

What should every hacker have available to them? That's right, a screwdriver (you have to get into those cases somehow). What…

$3.95

5

FavoritedFavorite19

Wish List

added to your cart!

SparkFun MicroMod Artemis Processor

In stock DEV-16401

Featuring the Artemis Module, this processor is capable of machine learning, Bluetooth, I2C, GPIO, PWM, SPI & packaged to fit…

$14.95

FavoritedFavorite8

Wish List

added to your cart!

microSD Card - 1GB (Class 4)

In stock COM-15107

For the times when all you need is a basic SD card this is the card for you. 1GB capacity is plenty to store MP3s or log envi…

$4.95

FavoritedFavorite6

Wish List

MicroMod Main Board

To hold the processor and function boards, you will need one Main board. Depending on your application, you may choose to have either one or two function boards.

added to your cart!

SparkFun MicroMod Main Board - Single

In stock DEV-18575

The MicroMod Main Board is a specialized carrier board that allows you to interface a MicroMod Processor Board with a single …

$14.95

FavoritedFavorite1

Wish List

added to your cart!

SparkFun MicroMod Main Board - Double

In stock DEV-18576

The MicroMod Main Board is a specialized carrier board that allows you to interface a MicroMod Processor Board with up to two…

$17.95

FavoritedFavorite1

Wish List

MicroMod Function Board

To add additional functionality to your Processor Board, you'll want to include one or two function boards when connecting them to the Main Board. Besides the MicroMod Environmental Function Board which this tutorial is focused on, you may descide to add the WiFi Function Board to the mix. Make sure to adjust the cart and include the MicroMod Main Board - Double as opposed to the Single when using two Function Boards. Check out the SparkFun catalog for other function boards.

added to your cart!

SparkFun MicroMod Environmental Function Board

In stock SEN-18632

The MicroMod Environmental Function Board includes three sensors to monitor air quality, humidity / temperature, & CO2 concen…

$149.95

FavoritedFavorite1

Wish List

added to your cart!

SparkFun MicroMod WiFi Function Board - ESP32

In stock WRL-18430

The SparkFun MicroMod ESP32 Function Board adds additional wireless options to MicroMod Processor Boards that do not have tha…

$14.95

FavoritedFavorite1

Wish List

Tools

You will need a screw driver to secure the Processor and Function boards.

added to your cart!

SparkFun Mini Screwdriver

In stock TOL-09146

This is just your basic reversible screwdriver - pocket sized! Both flat and phillips heads available. Comes with pin clip an…

$0.95

3

FavoritedFavorite7

Wish List

Suggested Reading

If you aren't familiar with the MicroMod ecosystem, we recommend reading here for an overview.

MicroMod Ecosystem

If you aren’t familiar with the following concepts, we also recommend checking out a few of these tutorials before continuing. Make sure to check the respective hookup guides for your processor board and function board to ensure that you are installing the correct USB-to-serial converter. You may also need to follow additional instructions that are not outlined in this tutorial to install the appropriate software.

Hardware Overview

This section goes over the important features on the MicroMod Environmental Function Board. Of course, we recommend checking out the Resources and Going Further for more information on each sensor.

Power

To power the board, you will need to apply power to a SparkFun Main Board. Power applied will connect to the Function Board's VIN pin, which will be regulated down for the rest of the board with the AP2112 3.3V/600mA voltage regulator.

SGP40

The board includes the Sensirion SGP40 sensor IC which measures air quality. The reserved I²C address for the SGP40 is 0x59. For easy reference, the default address for the SGP40 is labeled on the board.

SHTC3

The board includes the Sensirion SHTC3 sensor IC which measures humidity and temperature. The reserved I²C address for the SHTC3 is 0x70. For easy reference, the default address for the SHTC3 is labeled on the board.

STC31

The board includes the Sensirion STC31 sensor IC which measures CO₂ concentrations in N₂ and CO₂ in air. The reserved I²C address for the STC31 is 0x29. For easy reference, the default address for the STC31 is labeled on the board.

EEPROM

The board includes an I²C EEPROM. Unfortunately, this is not available for the user and was meant to hold board specific information.

LED

There is one LED to indicate when there is power available. You can disable the LED with the PWR jumper

Jumpers

The following jumpers are included to configure the board.

• PWR - By default, the jumper with the label PWR is closed. This jumper connects the 3.3V line and LED. Cutting this jumper will disable the LED.
• I²C Pull-up Resistors - By default, this three way jumper labeled I2C is closed and connects two pull-up resistors to the I²C data lines. If you have many devices on your I²C data lines, then you may consider cutting these two jumpers.
• STC31 Address Selection - There are three jumpers available on the board to adjust the STC31's address. By default, the jumpers are open. The alternative addresses for the sensor are 0x2A, 0x2B, and 0x2C. To select the address, you will need to close the jumper by adding a solder blob to one of the solder jumpers.

MicroMod Function Board Pinout

Depending on your window size, you may need to use the horizontal scroll bar at the bottom of the table to view the additional pin functions. Note that the M.2 connector pins on opposing sides are offset from each other as indicated by the bottom pins where it says (Not Connected)*. There is no connection to pins that have a "-" under the primary function.

• MicroMod Environment Function Board Pinout Table
• MicroMod General Processor Pinout Table
• MicroMod General Pin Descriptions

Board Dimensions

The board uses the standard MicroMod Function Board size which measures about 1.50"x2.56".

Hardware Hookup

If you have not already, make sure to check out the Getting Started with MicroMod: Hardware Hookup for information on inserting your Processor and Function Boards to the Main Board.

After securing the Processor and Function Board to the Main Board, your setup should look like the image below. Connect a USB Type C Cable to begin programming your Processor Board. In this case, we used the MicroMod Main Board - Single, MicroMod Artemis Processor, and MicroMod Environmental Function Board.

Software Installation

Arduino Board Definitions and Driver

We'll assume that you installed the necessary board files and drivers for your Processor Board. In this case, we used the MicroMod Artemis Processor Board which uses the CH340 USB-to-serial converter. If you are using a Processor Board, make sure to check out its hookup guide for your Processor Board.

Arduino Library

The SparkFun SGP40, SHTC3, and STC3X Arduino libraries can be downloaded with the Arduino library manager by searching 'SparkFun SGP40,' 'SHTC3,' and 'STC3X'. Or you can grab the zip here from each respective GitHub repository (SGP40, SHTC3, STC3X) to manually install:

Arduino Examples

Example 1: Reading SHTC3, STC31, and SGP40

Below is the combined example to read SHTC3, STC31, and SGP40. If you have not already, select your Board (in this case the MicroMod Artemis), and associated COM port. Copy and paste the code below in your Arduino IDE. Hit the upload button and set the serial monitor to 115200 baud.

language:c
/******************************************************************************

  WRITTEN BY: Ho Yun "Bobby" Chan
  @ SparkFun Electronics
  DATE: 10/19/2021
  GITHUB REPO: https://github.com/sparkfun/MicroMod_Environmental_Sensor_Function_Board
  DEVELOPMENT ENVIRONMENT SPECIFICS:
    Firmware developed using Arduino IDE v1.8.12

  ========== DESCRIPTION==========
  This example code combines example codes from the SHTC3, STC31, and SGP40 libraries.
  Most of the steps to obtain the measurements are the same as the example code.
  Generic object names were renamed (e.g. mySensor => mySGP40 and mySTC3x).

     Example 1: Basic Relative Humidity and Temperature Readings  w/ SHTC3; Written by Owen Lyke
     Example 2: PHT (SHTC3) Compensated CO2 Readings w/ STC31; Written by Paul Clark and based on earlier code by Nathan Seidle
     Example 1: Basic VOC Index w/ SGP40; Written by Paul Clark

  Open a Serial Monitor at 115200 baud to view the readings!

  Note: You may need to wait about ~5 minutes after starting up the code before VOC index
  has any values.

  ========== HARDWARE CONNECTIONS ==========
  MicroMod Artemis Processor Board => MicroMod Main Board => MicroMod Environmental Function Board (with SHTC3, STC31, and SGP40)

  Feel like supporting open source hardware?
  Buy a board from SparkFun!
       MicroMod MicroMod Artemis Processor   | https://www.sparkfun.com/products/16401
       MicroMod Main Board - Single          | https://www.sparkfun.com/products/18575
       MicroMod Environmental Function Board | https://www.sparkfun.com/products/18632

  You can also get the sensors individually.

       Qwiic SHTC3 | https://www.sparkfun.com/products/16467
       Qwiic STC31 | https://www.sparkfun.com/products/18385
       Qwiic SGP40 | https://www.sparkfun.com/products/17729

  LICENSE: This code is released under the MIT License (http://opensource.org/licenses/MIT)

******************************************************************************/



#include <Wire.h>

#include "SparkFun_SHTC3.h" //Click here to get the library: http://librarymanager/All#SparkFun_SHTC3
SHTC3 mySHTC3; // Create an object of the SHTC3 class

#include "SparkFun_STC3x_Arduino_Library.h" //Click here to get the library: http://librarymanager/All#SparkFun_STC3x
STC3x mySTC3x; // Create an object of the mySTC3x class

#include "SparkFun_SGP40_Arduino_Library.h" // Click here to get the library: http://librarymanager/All#SparkFun_SGP40
SGP40 mySGP40; //Create an object of the SGP40 class

float RH = 0.00; // Variable to keep track of SHTC3 temperature compensation for the STC31
float temperature = 0.00; // Variable to keep track of SHTC3 relative humidity compensation for the STC31






void setup() {

  Serial.begin(115200);
  //while (!Serial) ; // Wait for Serial Monitor/Plotter to open for Processors with Native USB (i.e. SAMD51)
  Serial.println(F("Initializing Combined Example w/ SGP40, SHTC3, and STC31."));
  Wire.begin();

  //mySTC3x.enableDebugging(); // Uncomment this line to get helpful debug messages on Serial
  //mySGP40.enableDebugging(); // Uncomment this line to print useful debug messages to Serial



  if (mySHTC3.begin() != SHTC3_Status_Nominal)
  {
    Serial.println(F("SHTC3 not detected. Please check wiring. Freezing..."));
    while (1)
      ; // Do nothing more
  }

  if (mySTC3x.begin() == false)
  {
    Serial.println(F("STC3x not detected. Please check wiring. Freezing..."));
    while (1)
      ; // Do nothing more
  }

  if (mySGP40.begin() == false)
  {
    Serial.println(F("SGP40 not detected. Check connections. Freezing..."));
    while (1)
      ; // Do nothing more
  }



  //We need to tell the STC3x what binary gas and full range we are using
  //Possible values are:
  //  STC3X_BINARY_GAS_CO2_N2_100   : Set binary gas to CO2 in N2.  Range: 0 to 100 vol%
  //  STC3X_BINARY_GAS_CO2_AIR_100  : Set binary gas to CO2 in Air. Range: 0 to 100 vol%
  //  STC3X_BINARY_GAS_CO2_N2_25    : Set binary gas to CO2 in N2.  Range: 0 to 25 vol%
  //  STC3X_BINARY_GAS_CO2_AIR_25   : Set binary gas to CO2 in Air. Range: 0 to 25 vol%
  if (mySTC3x.setBinaryGas(STC3X_BINARY_GAS_CO2_AIR_25) == false)
  {
    Serial.println(F("Could not set the binary gas! Freezing..."));
    while (1)
      ; // Do nothing more
  }



  //We can compensate for temperature and relative humidity using the readings from the SHTC3

  if (mySHTC3.update() != SHTC3_Status_Nominal) // Request a measurement
  {
    Serial.println(F("Could not read the RH and T from the SHTC3! Freezing..."));
    while (1)
      ; // Do nothing more
  }

  //In case the ‘Set temperature command’ has been used prior to the measurement command,
  //the temperature value given out by the STC31 will be that one of the ‘Set temperature command’.
  //When the ‘Set temperature command’ has not been used, the internal temperature value can be read out.
  temperature = mySHTC3.toDegC(); // "toDegC" returns the temperature as a floating point number in deg C
  Serial.print(F("Setting STC3x temperature to "));
  Serial.print(temperature, 2);
  Serial.print(F("C was "));
  if (mySTC3x.setTemperature(temperature) == false)
    Serial.print(F("not "));
  Serial.println(F("successful"));

  RH = mySHTC3.toPercent(); // "toPercent" returns the percent humidity as a floating point number
  Serial.print(F("Setting STC3x RH to "));
  Serial.print(RH, 2);
  Serial.print(F("% was "));
  if (mySTC3x.setRelativeHumidity(RH) == false)
    Serial.print(F("not "));
  Serial.println(F("successful"));

  //If we have a pressure sensor available, we can compensate for ambient pressure too.
  //As an example, let's set the pressure to 840 mbar (== SF Headquarters)
  uint16_t pressure = 840;
  Serial.print(F("Setting STC3x pressure to "));
  Serial.print(pressure);
  Serial.print(F("mbar was "));
  if (mySTC3x.setPressure(pressure) == false)
    Serial.print(F("not "));
  Serial.println(F("successful"));

  Serial.println(F("Note: Relative humidity and temperature compensation for the STC31 will be updated frequently in the main loop() function."));

} //end setup()






void loop() {

  //==============================
  //==========READ SHTC3==========
  //==============================
  //minimum update rate = ~100Hz

  SHTC3_Status_TypeDef result = mySHTC3.update();           // Call "update()" to command a measurement, wait for measurement to complete, and update the RH and T members of the object

  RH = mySHTC3.toPercent();                                 // "toPercent" returns the percent humidity as a floating point number
  Serial.print(F("RH = "));
  Serial.print(RH);

  Serial.print(F("%, T = "));
  Serial.print(mySHTC3.toDegF());                           // "toDegF" return the temperature as a flaoting point number in deg F
  Serial.print(F(" deg F, "));

  temperature = mySHTC3.toDegC();                           // "toDegC" returns the temperature as a floating point number in deg C
  Serial.print(temperature);
  Serial.print(F(" deg C"));

  if (mySHTC3.lastStatus == SHTC3_Status_Nominal)           // You can also assess the status of the last command by checking the ".lastStatus" member of the object
  {
    Serial.println("");                                         //Sample data good, no need to output a message
  }
  else {
    Serial.print(F(",     Update failed, error: "));        //notify user if there is an error
    errorDecoder(mySHTC3.lastStatus);
    Serial.println("");
  }



  //==============================
  //==========READ STC31==========
  //==============================
  //minimum update rate = 1Hz


  if (mySTC3x.setRelativeHumidity(RH) == false)
    Serial.print(F("Unable to set STC31 Relative Humidity with SHTC3."));

  if (mySTC3x.setTemperature(temperature) == false)
    Serial.println(F("Unable to set STC31 Temperature with SHTC3."));


  Serial.print(F("CO2(%): "));

  if (mySTC3x.measureGasConcentration())                   // measureGasConcentration will return true when fresh data is available
  {
    Serial.println(mySTC3x.getCO2(), 2);
  }
  else
  {
    Serial.print(mySTC3x.getCO2(), 2);
    Serial.println(F(",     (old STC3 sample reading, STC31 was not able to get fresh data yet)"));  //output this note to indicate  when we are not able to obtain a new measurement
  }



  //==============================
  //==========READ SGP40==========
  //==============================
  //minimum update rate = 1Hz

  Serial.print(F("VOC Index is: "));
  Serial.println(mySGP40.getVOCindex()); //Get the VOC Index using the default RH (50%) and T (25C)



  //================================
  //=========SPACE & DELAY==========
  //================================
  //Serial.println("");// Uncomment this line to add some space between readings for the Serial Monitor
  delay(1000); //Wait 1 second - the Sensirion VOC and CO2 algorithms expects a sample rate of 1Hz

}//end loop()





void errorDecoder(SHTC3_Status_TypeDef message)                             // The errorDecoder function prints "SHTC3_Status_TypeDef" results in a human-friendly way
{
  switch (message)
  {
    case SHTC3_Status_Nominal : Serial.print("Nominal"); break;
    case SHTC3_Status_Error : Serial.print("Error"); break;
    case SHTC3_Status_CRC_Fail : Serial.print("CRC Fail"); break;
    default : Serial.print("Unknown return code"); break;
  }
}

Example 2: Reading SHTC3, STC31, and SGP40 in CSV

Below is the same combined code but formatted for CSV. If you have not already, select your Board (in this case the MicroMod Artemis), and associated COM port. Copy and paste the code below in your Arduino IDE. Hit the upload button and set the serial monitor to 115200 baud.

language:c
/******************************************************************************

  WRITTEN BY: Ho Yun "Bobby" Chan
  @ SparkFun Electronics
  DATE: 10/19/2021
  GITHUB REPO: https://github.com/sparkfun/MicroMod_Environmental_Sensor_Function_Board
  DEVELOPMENT ENVIRONMENT SPECIFICS:
    Firmware developed using Arduino IDE v1.8.12

  ========== DESCRIPTION==========
  This example code combines example codes from the SHTC3, STC31, and SGP40 libraries.
  Most of the steps to obtain the measurements are the same as the example code.
  Generic object names were renamed (e.g. mySensor => mySGP40 and mySTC3x).

     Example 1: Basic Relative Humidity and Temperature Readings  w/ SHTC3; Written by Owen Lyke
     Example 2: PHT (SHTC3) Compensated CO2 Readings w/ STC31; Written by Paul Clark and based on earlier code by Nathan Seidle
     Example 1: Basic VOC Index w/ SGP40; Written by Paul Clark

  Open a Serial Monitor/Plotter at 115200 baud to view the readings!

  Note: You may need to wait about ~5 minutes after starting up the code before VOC index
  has any values.

  ========== HARDWARE CONNECTIONS ==========
  MicroMod Artemis Processor Board => MicroMod Main Board => MicroMod Environmental Function Board (with SHTC3, STC31, and SGP40)

  Feel like supporting open source hardware?
  Buy a board from SparkFun!
       MicroMod MicroMod Artemis Processor   | https://www.sparkfun.com/products/16401
       MicroMod Main Board - Single          | https://www.sparkfun.com/products/18575
       MicroMod Environmental Function Board | https://www.sparkfun.com/products/18632

  You can also get the sensors individually.
       SHTC3 | https://www.sparkfun.com/products/16467
       STC31 | https://www.sparkfun.com/products/18385
       SGP40 | https://www.sparkfun.com/products/17729

  LICENSE: This code is released under the MIT License (http://opensource.org/licenses/MIT)

******************************************************************************/



#include <Wire.h>

#include "SparkFun_SHTC3.h" //Click here to get the library: http://librarymanager/All#SparkFun_SHTC3
SHTC3 mySHTC3; // Create an object of the SHTC3 class

#include "SparkFun_STC3x_Arduino_Library.h" //Click here to get the library: http://librarymanager/All#SparkFun_STC3x
STC3x mySTC3x; // Create an object of the STC3x class

#include "SparkFun_SGP40_Arduino_Library.h" // Click here to get the library: http://librarymanager/All#SparkFun_SGP40
SGP40 mySGP40; //Create an object of the SGP40 class

float RH = 0.00; // Variable to keep track of SHTC3 temperature compensation for the STC31
float temperature = 0.00; // Variable to keep track of SHTC3 relative humidity compensation for the STC31

//Debug mode, comment one of these lines out using a syntax
//for a single line comment ("//"):
#define DEBUG 0     //0 = Output for Serial Plotter, CSV
//#define DEBUG 1     //1 = Output for Serial Monitor





void setup() {

  Serial.begin(115200);
  //while (!Serial) ; // Wait for Serial Monitor/Plotter to open for Processors with Native USB (i.e. SAMD51)


#if DEBUG
  Serial.println(F("Initializing Combined Example w/ SGP40, SHTC3, and STC31."));
#else
  Serial.println(F("RH,degF,degC,SHTC3_Valid,RH_Compensate_Valid,degC_Compensate_Valid,CO2%,STC31_Valid,VOC_Index"));
#endif

  Wire.begin();

  //mySTC3x.enableDebugging(); // Uncomment this line to get helpful debug messages on Serial
  //mySGP40.enableDebugging(); // Uncomment this line to print useful debug messages to Serial



  if (mySHTC3.begin() != SHTC3_Status_Nominal)
  {
#if DEBUG
    Serial.println(F("SHTC3 not detected. Please check wiring. Freezing..."));
#endif
    while (1)
      ; // Do nothing more
  }

  if (mySTC3x.begin() == false)
  {
#if DEBUG
    Serial.println(F("STC3x not detected. Please check wiring. Freezing..."));
#endif
    while (1)
      ; // Do nothing more
  }

  if (mySGP40.begin() == false)
  {
#if DEBUG
    Serial.println(F("SGP40 not detected. Check connections. Freezing..."));
#endif
    while (1)
      ; // Do nothing more
  }



  //We need to tell the STC3x what binary gas and full range we are using
  //Possible values are:
  //  STC3X_BINARY_GAS_CO2_N2_100   : Set binary gas to CO2 in N2.  Range: 0 to 100 vol%
  //  STC3X_BINARY_GAS_CO2_AIR_100  : Set binary gas to CO2 in Air. Range: 0 to 100 vol%
  //  STC3X_BINARY_GAS_CO2_N2_25    : Set binary gas to CO2 in N2.  Range: 0 to 25 vol%
  //  STC3X_BINARY_GAS_CO2_AIR_25   : Set binary gas to CO2 in Air. Range: 0 to 25 vol%
  if (mySTC3x.setBinaryGas(STC3X_BINARY_GAS_CO2_AIR_25) == false)
  {
#if DEBUG
    Serial.println(F("Could not set the binary gas! Freezing..."));
#endif
    while (1)
      ; // Do nothing more
  }



  //We can compensate for temperature and relative humidity using the readings from the SHTC3

  if (mySHTC3.update() != SHTC3_Status_Nominal) // Request a measurement
  {
#if DEBUG
    Serial.println(F("Could not read the RH and T from the SHTC3! Freezing..."));
#endif
    while (1)
      ; // Do nothing more
  }

  //In case the ‘Set temperature command’ has been used prior to the measurement command,
  //the temperature value given out by the STC31 will be that one of the ‘Set temperature command’.
  //When the ‘Set temperature command’ has not been used, the internal temperature value can be read out.
  temperature = mySHTC3.toDegC(); // "toDegC" returns the temperature as a floating point number in deg C
#if DEBUG
  Serial.print(F("Setting STC3x temperature to "));
  Serial.print(temperature, 2);
  Serial.print(",");
  Serial.print(F("C was "));
#endif

  if (mySTC3x.setTemperature(temperature) == false) {
#if DEBUG
    Serial.print(F("not "));
#endif
  }
#if DEBUG
  Serial.println(F("successful"));
#endif

  RH = mySHTC3.toPercent(); // "toPercent" returns the percent humidity as a floating point number

#if DEBUG
  Serial.print(F("Setting STC3x RH to "));
  Serial.print(RH, 2);
  Serial.print(",");
  Serial.print(F("% was "));
#endif

  if (mySTC3x.setRelativeHumidity(RH) == false) {
#if DEBUG
    Serial.print(F("not "));
#endif
  }
#if DEBUG
  Serial.println(F("successful"));
#endif



  //If we have a pressure sensor available, we can compensate for ambient pressure too.
  //As an example, let's set the pressure to 840 mbar (== SF Headquarters)
  uint16_t pressure = 840;

#if DEBUG
  Serial.print(F("Setting STC3x pressure to "));
  Serial.print(pressure);
  Serial.print(F("mbar was "));
#endif

  if (mySTC3x.setPressure(pressure) == false) {
#if DEBUG
    Serial.print(F("not "));
#endif
  }
#if DEBUG
  Serial.println(F("successful"));

  Serial.println(F("Note: Relative humidity and temperature compensation for the STC31 will be updated frequently in the main loop() function."));
#endif

} //end setup()





void loop() {


  //==============================
  //======DEBUG TURNED ON=========
  //==============================
#if DEBUG
  //==============================
  //==========READ SHTC3==========
  //==============================
  //minimum update rate = ~100Hz

  SHTC3_Status_TypeDef result = mySHTC3.update();           // Call "update()" to command a measurement, wait for measurement to complete, and update the RH and T members of the object

  RH = mySHTC3.toPercent();                                 // "toPercent" returns the percent humidity as a floating point number
  Serial.print(F("RH = "));
  Serial.print(RH);

  Serial.print(F("%, T = "));
  Serial.print(mySHTC3.toDegF());                           // "toDegF" return the temperature as a flaoting point number in deg F
  Serial.print(F(" deg F, "));

  temperature = mySHTC3.toDegC();                           // "toDegC" returns the temperature as a floating point number in deg C
  Serial.print(temperature);
  Serial.print(F(" deg C"));

  if (mySHTC3.lastStatus == SHTC3_Status_Nominal)           // You can also assess the status of the last command by checking the ".lastStatus" member of the object
  {
    Serial.println("");                                         //Sample data good, no need to output a message
  }
  else {
    Serial.print(F(",     Update failed, error: "));        //notify user if there is an error
    errorDecoder(mySHTC3.lastStatus);
    Serial.println("");
  }



  //==============================
  //==========READ STC31==========
  //==============================
  //minimum update rate = 1Hz


  if (mySTC3x.setRelativeHumidity(RH) == false)
    Serial.print(F("Unable to set STC31 Relative Humidity with SHTC3."));

  if (mySTC3x.setTemperature(temperature) == false)
    Serial.println(F("Unable to set STC31 Temperature with SHTC3."));


  Serial.print(F("CO2(%): "));

  if (mySTC3x.measureGasConcentration())                   // measureGasConcentration will return true when fresh data is available
  {
    Serial.println(mySTC3x.getCO2(), 2);
  }
  else
  {
    Serial.print(mySTC3x.getCO2(), 2);
    Serial.println(F(",     (old STC3 sample reading, STC31 was not able to get fresh data yet)"));  //output this note to indicate  when we are not able to obtain a new measurement
  }



  //==============================
  //==========READ SGP40==========
  //==============================
  //minimum update rate = 1Hz

  Serial.print(F("VOC Index is: "));
  Serial.println(mySGP40.getVOCindex()); //Get the VOC Index using the default RH (50%) and T (25C)





  //==============================
  //=====DEBUG TURNED OFF=========
  //==============================
#else
  //==============================
  //==========READ SHTC3==========
  //==============================
  //minimum update rate = ~100Hz

  SHTC3_Status_TypeDef result = mySHTC3.update();           // Call "update()" to command a measurement, wait for measurement to complete, and update the RH and T members of the object

  RH = mySHTC3.toPercent();
  Serial.print(RH);
  Serial.print(",");
  Serial.print(mySHTC3.toDegF());
  Serial.print(",");
  temperature = mySHTC3.toDegC();                           // "toDegC" returns the temperature as a floating point number in deg C
  Serial.print(temperature);
  Serial.print(",");

  if (mySHTC3.lastStatus == SHTC3_Status_Nominal)           // You can also assess the status of the last command by checking the ".lastStatus" member of the object
  {
    Serial.print("1");                                         //Sample data good, no need to output a message
    Serial.print(",");
  }
  else
  {
    Serial.print("0");                                         //Sample data bad, no need to output a message
    Serial.print(",");
  }



  //==============================
  //==========READ STC31==========
  //==============================
  //minimum update rate = 1Hz


  if (mySTC3x.setRelativeHumidity(RH) == false)
  {
    //Serial.print(F("Unable to set STC31 Relative Humidity with SHTC3."));
    Serial.print("0");
    Serial.print(",");
  }
  else
  {
    Serial.print("1");
    Serial.print(",");
  }

  if (mySTC3x.setTemperature(temperature) == false)
  {
    //Serial.println(F("Unable to set STC31 Temperature with SHTC3."));
    Serial.print("0");
    Serial.print(",");
  }
  else
  {
    Serial.print("1");
    Serial.print(",");
  }

  if (mySTC3x.measureGasConcentration())                   // measureGasConcentration will return true when fresh data is available
  {
    Serial.print(mySTC3x.getCO2(), 2);
    Serial.print(",");
    Serial.print("1");                                     //Fresh Data
    Serial.print(",");
  }
  else
  {
    Serial.print(mySTC3x.getCO2(), 2);
    Serial.print(",");
    Serial.print("0");                                     //Data not fresh
    Serial.print(",");
  }



  //==============================
  //==========READ SGP40==========
  //==============================
  //minimum update rate = 1Hz

  Serial.println(mySGP40.getVOCindex()); //Get the VOC Index using the default RH (50%) and T (25C)

#endif



  //================================
  //=========SPACE & DELAY==========
  //================================
  //Serial.println("");// Uncomment this line to add some space between readings for the Serial Monitor
  delay(1000); //Wait 1 second - the Sensirion VOC algorithm expects a sample rate of 1Hz

}//end loop()





void errorDecoder(SHTC3_Status_TypeDef message)                             // The errorDecoder function prints "SHTC3_Status_TypeDef" resultsin a human-friendly way
{
  switch (message)
  {
    case SHTC3_Status_Nominal : Serial.print("Nominal"); break;
    case SHTC3_Status_Error : Serial.print("Error"); break;
    case SHTC3_Status_CRC_Fail : Serial.print("CRC Fail"); break;
    default : Serial.print("Unknown return code"); break;
  }
}

Troubleshooting

Resources and Going Further

Now that you've successfully got your MicroMod Environmental Function Board up and running, it's time to incorporate it into your own project! For more information, check out the resources below:

• Schematic (PDF)
• Eagle Files (ZIP)
• Board Dimensions (PNG)
• SGP40
  • SGP40 Datasheet (PDF)
  • VOC Index for Experts (PDF)
  • SGP40 Design In Guide (PDF)
  • SGP40 Quick Testing Guide (PDF)
• SHTC3
  • SHTC3 Datasheet (PDF)
• STC31
  • STC31 Datasheet (PDF)
  • STC Field Calibration Guide (PDF)
  • STC Design-In Guide (PDF)
• Arduino Libraries
  • SGP40
  • SHTC3
  • STC3X
• GitHub Hardware Repo
• SFE Product Showcase

Need some inspiration for your next project? Check out some of these related tutorials with MicroMod:

learn.sparkfun.com | CC BY-SA 3.0 | SparkFun Electronics | Niwot, Colorado

SparkFun RTK Facet Hookup Guide a learn.sparkfun.com tutorial

Available online at: http://sfe.io/t2188

Introduction

The RTK Facet from SparkFun is our most advanced GNSS receiver to date. It's your one stop shop for high precision geolocation and surveying needs. For basic users, it’s incredibly easy to get up and running and for advanced users, the RTK Facet is a flexible and powerful tool.

added to your cart!

SparkFun RTK Facet

In stock GPS-19029

The SparkFun RTK Facet is a fully enclosed GNSS receiver for centimeter-level positioning. Perfect for high precision geoloca…

$699.95

FavoritedFavorite0

Wish List

With just a few minutes of setup, the RTK Facet is one of the fastest ways to take centimeter grade measurements.

By connecting your phone to the RTK Facet over Bluetooth, your phone can act as the radio link to provide correction data as well as receive the NMEA output from the device. It’s how $10,000 surveying devices have been operating for the past decade - we just made it easier, smaller, and a lot cheaper.

Required Materials

The RTK Facet has all you need built into one small unit. In addition, the RTK Facet Kit includes everything you might need as well. The only thing you need to add is your own tablet or cell phone (Android and IOS supported).

Depending on your setup you may want to use your phone for RTCM correction data. If a source is not available online, you will need a 2nd RTK Facet setup in base mode and a radio link connecting the Base to the Rover. We'll go into details but we designed RTK Facet to work with these 100mW 915MHz telemetry radios out of the box.

Serial Telemetry Radio Kit - 915MHz, 100mW

Out of stock WRL-15007

The 915MHz Serial Telemetry Radio Kit is a lightweight and inexpensive open source radio platform that can allow for ranges o…

FavoritedFavorite12

Wish List

To charge the RTK Facet you will need a USB C cable and a power supply. These are included with the kit but any USB C port should charge the Facet at a maximum rate of 1A per hour.

added to your cart!

USB 2.0 Type-C Cable - 1 Meter

In stock CAB-16905

1 Meter USB Type C to Type C cable USB 2.0 data transfer capabilities.

$4.50

FavoritedFavorite2

Wish List

added to your cart!

Reversible USB A to C Cable - 0.8m

In stock CAB-15425

These 0.8m cables have minor modifications that allow them to be be plugged into their ports regardless of orientation on the…

$4.95

1

FavoritedFavorite5

Wish List

added to your cart!

USB Wall Charger - 5V, 2A

In stock TOL-16893

This USB AC to DC power supply will do 5V at 2A!

$5.95

FavoritedFavorite1

Wish List

added to your cart!

USB-C Wall Adapter - 5.1V, 3A (Black)

32 available TOL-16272

This is a USB Type-C Power Supply that is compatible with the Raspberry Pi 4.

$4.95

FavoritedFavorite4

Wish List

Suggested Reading

GNSS RTK is an incredible feat of engineering that has been made easy to use by powerful GNSS receivers such as the ZED-F9P by u-blox (the receiver inside RTK Facet). The process of setting up an RTK system will be covered in this tutorial but if you want to know more about RTK here are some good tutorials to brush up on:

Hardware Overview

The RTK Facet is a fully enclosed, preprogrammed device. There are very few things to worry about or configure but we will cover the basics.

Power/Setup Button

The RTK Facet has one button used for both Power and Setup for in-field configuration changes. Pressing and holding the Power button will cause it to power on or off. Short pressing the button will cause the RTK Facet to change modes.

This device can be used in four modes:

• GNSS Positioning (~30cm accuracy) - also known as 'Rover'
• GNSS Positioning with RTK (1.4cm accuracy) - also known as 'Rover with RTK Fix'
• GNSS Base Station
• GNSS Base Station NTRIP Server

At Power On the device will enter Rover or Base mode; whichever state the device was in at the last power down. When the POWER/SETUP button is pressed momentarily, a menu is presented to change the RTK Facet to Rover or Base mode. The display will indicate the change with a small car or flag icon.

In Rover mode the RTK Facet will receive L1 and L2 GNSS signals from the four constellations (GPS, GLONASS, Galileo, and BeiDou) and calculate the position based on these signals. Similar to a standard grade GPS receiver, the RTK Facet will output industry standard NMEA sentences at 4Hz and broadcast them over any paired Bluetooth device. The end user will need to parse the NMEA sentences using commonly available mobile apps, GIS products, or embedded devices (there are many open source libraries). Unlike standard grade GPS receivers that have 2500m accuracy, the accuracy in this mode is approximately 300mm horizontal positional accuracy with a good grade L1/L2 antenna.

When the device is in Rover mode and RTCM correction data is sent over Bluetooth or into the radio port, the device will automatically enter Positioning with RTK mode. In this mode RTK Facet will receive L1/L2 signals from the antenna and correction data from a base station. The receiver will quickly (within a second) obtain RTK float, then fix. The NMEA sentences will have increased accuracy of 14mm horizontal and 10mm vertical accuracy. The RTCM correction data is most easily obtained over the internet using a free app on your phone (see SW Maps or Lefebure NTRIP) and sent over Bluetooth to the RTK Facet but RTCM can also be delivered over an external cellular or radio link to a 2nd RTK Facet setup as a base station.

In Base mode the device will enter Base Station mode. This is used when the device is mounted to a fixed position (like a tripod or roof). The RTK Facet will initiate a survey. After 60 to 120 seconds the survey will complete and the RTK Facet will begin transmitting RTCM correction data out the radio port. A base is often used in conjunction with a second RTK Facet (or RTK Surveyor) unit set to 'Rover' to obtain the 14mm accuracy. Said differently, the Base sits still and sends correction data to the Rover so that the Rover can output a really accurate position. You’ll create an RTK system without any other setup.

Power

The Power button turns on and off the unit. Press and hold the power button until the display illuminates. Press and hold the power button at any time to turn the unit off.

The RTK Facet has a large, built-in 6000mAh lithium polymer battery that will enable over 25 hours of field use between charging. If more time is needed a common USB power bank can be attached boosting the field time to any amount needed.

Charge LED

The Charge LED is located on the front face. It will illuminate any time there is an external power source and will turn off when the internal battery is charged. With the unit fully powered down, charging takes approximately 6 hours from a 1A wall supply or 12 hours from a standard USB port. The RTK Facet can run while being charged but it increases the charge time. Using an external USB battery bank to run the device for extended periods or running the device on a permanent wall power source is supported.

Connectors

There are a variety of connectors protected by a dust flap.

USB:

This USB C connector is used for three purposes:

• Charging the device
• Configuring the RTK Facet, and reprogramming the ESP32
• Directly configuring and inspecting the ZED-F9P GNSS receiver

There is a USB hub built into the RTK Facet. When you attach the device to your computer it will enumerate as two COM ports.

In the image above, the USB Serial Device is the ZED-F9P and the USB-SERIAL CH340 is the ESP32.

Configuring the RTK Facet can be done over the USB-Serial CH340 COM port via serial text menu. Various debug messages are printed to this port at 115200bps and a serial menu can be opened to configure advanced settings.

Configuring the ZED-F9P can be configured over the USB Serial Device port using u-center. It’s not necessary in normal operation but is handy for tailoring the receiver to specific applications. As an added perk, the ZED-F9P can be detected automatically by some mobile phones and tablets. If desired, the receiver can be directly connected to a compatible phone or tablet removing the need for a Bluetooth connection.

Radio:

This port is used when an external cellular or radio link is needed. This port is not used if you transfer RTCM from your phone to the RTK Facet over Bluetooth.

This 4-pin JST connector can be used to allow RTCM correction data to flow into the device when it is acting as a rover or out of the device when it is acting as a base. The connector is a 4-pin locking 1.25mm JST SMD connector (part#: SM04B-GHS-TB, mating connector part#: GHR-04V-S). The RTK Facet comes with a cable to interface to this connector but additional cables can be purchased. You will most likely connect this port to one of our Serial Telemetry Radios if you don’t have access to a correction source on the internet. The pinout is 3.5-5.5V / TX / RX / GND from left to right as pictured. 3.5V to 5.5V is provided by this connector to power a radio with a voltage that depends on the power source. If USB is connected to the RTK Facet then voltage on this port will be 5V (+/-10%). If running off of the internal battery then voltage on this port will vary with the battery voltage (3.5V to 4.2V depending on the state of charge). This port is capable of sourcing up to 600mA and is protected by a PTC (resettable fuse). This port should not be connected to a power source.

Data:

This port is used when an external system is connected such as a rover, car, timing equipment, camera triggers, etc. This port is not used if you transfer NMEA positional data to your phone from the RTK Facet over Bluetooth.

This 4-pin JST connector is used to output and input a variety of data to the RTK Facet. The connector is a 4-pin locking 1.25mm JST SMD connector (part#: SM04B-GHS-TB, mating connector part#: GHR-04V-S). The RTK Facet comes with a cable to interface to this connector but additional cables can be purchased.

Internally the Data connector is connected to a digital mux allowing one of four software selectable setups:

• NMEA - The TX pin outputs any enabled messages (NMEA, UBX, and RTCM) at a default of 460,800bps (configurable 9600 to 921600bps). The RX pin can receive RTCM for RTK and can also receive UBX configuration commands if desired.
• PPS/Trigger - The TX pin outputs the pulse-per-second signal that is accurate to 30ns RMS. The RX pin is connected to the EXTINT pin on the ZED-F9P allowing for events to be measured with incredibly accurate nano-second resolution. Useful for things like audio triangulation. See the Timemark section of the ZED-F9P integration for more information.
• I2C - The TX pin operates as SCL, RX pin as SDA on the I2C bus. This allows additional sensors to be connected to the I2C bus.
• GPIO - The TX pin operates as a DAC capable GPIO on the ESP32. The RX pin operates as a ADC capable input on the ESP32. This is useful for custom applications.

Most applications do not need to utilize this port and will send the NMEA position data over Bluetooth. This port can be useful for sending position data to an embedded microcontroller or single board computer. The pinout is 3.3V / TX / RX / GND. 3.3V from left to right as pictured, which is provided by this connector to power a remote device if needed. While the port is capable of sourcing up to 600mA, we do not recommend more than 300mA. This port should not be connected to a power source.

microSD:

This slot accepts standard microSD cards up to 32GB formatted for FAT16 or FAT32. Logging any of 67 messages at up to 4Hz is supported for all constellations.

The following 67 messages are supported for logging:

Qwiic:

This 4-pin Qwiic connector exposes the I2C bus of the ESP32 WROOM module. Currently, there is no firmware support for adding I²C devices to the RTK Facet but support may be added in the future.

Antenna:

It's built in! Housed under the dome of the RTK Facet is a surveyor grade L1/L2 antenna. It is the same element found within our GNSS Multi-Band L1/L2 Surveying Antenna. Its datasheet is available here.

The built in antenna has an ARP of 61.4mm from the base to the measuring point of the L1 antenna and an ARP of 57.4mm to the measuring point of the L2 antenna.

Power

The RTK Facet has a built in 6000mAh battery and consumes approximately 240mA worst case with Bluetooth connection active and GNSS fully tracking. This will allow for around 25 hours of use in the field. If more time is needed in the field a standard USB power bank can be attached. If a 10,000mAh bank is attached one can estimate 56 hours of run time assuming 25% is lost to efficiencies of the power bank and charge circuit within RTK Facet.

The RTK Facet can be charged from any USB port or adapter. The charge circuit is rated for 1000mA so USB 2.0 ports will charge at 500mA and USB 3.0+ ports will charge at 1A.

To quickly view the state of charge, turn on the unit. The battery icon will indicate the following:

• 3 bars: >75% capacity remain
• 2 bars: >50% capacity remain
• 1 bar: >25% capacity remain
• 0 bars: <25% capacity remain

Hardware Overview - Advanced Features

The RTK Facet is a hacker’s delight. Under the hood of the RTK Facet is an ESP32 WROOM connected to a ZED-F9P as well as some peripheral hardware (LiPo fuel gauge, microSD, etc). It is programmed in Arduino and can be tailored by the end user to fit their needs.

ZED-F9P GNSS Receiver

The ZED-F9P GNSS receiver is configured over I²C and uses two UARTs to output NMEA (UART1) and input/output RTCM (UART2). In general, the ESP32 harvests the data from the ZED-F9Ps UART1 for Bluetooth transmission and logging to SD.

ESP32

The ESP32 uses a standard USB to serial conversion IC (CH340) to program the device. You can use the ESP32 core for Arduino or Espressif’s IoT Development Framework (IDF).

The CH340 automatically resets and puts the ESP32 into bootload mode as needed. However, the reset pin of the ESP32 is brought out to an external 2-pin 0.1” footprint if an external reset button is needed.

LiPo and Charging

The RTK Facet houses a standard 6000mAh 3.7V LiPo. The charge circuit is set to 1A so with an appropriate power source, charging an empty battery should take a little over six hours. USB C on the RTK Facet is configured for 2A draw so if the user attaches to a USB 3.0 port, the charge circuit should operate near the 1A max. If a user attaches to a USB 2.0 port, the charge circuit will operate at 500mA. This charge circuit also incorporates a 42C upper temperature cutoff to insure the LiPo cannot be charged in dangerous conditions.

Fuel Gauge and Accelerometer

The MAX17048 is a simple to use fuel gauge IC that gives the user a statement of charge (SOC) that is basically a 0 to 100% report. The MAX17048 has a sophisticated algorithm to figure out what the SOC is based on cell voltage that is beyond the scope of this tutorial but for our purposes, allows us to reliably view the battery level when the unit is on.

The RTK Facet also incorporates a the LIS2DH12 triple-axis accelerometer to aid in leveling in the field.

Qwiic

An internal Qwiic connector is included in the unit for future expansion. Currently the stock RTK Facet does not support any additional Qwiic sensors or display but users may add support for their own application.

microSD

A microSD socket is situated on the ESP32 SPI bus. Any microSD up to 32GB is supported. RTK Facet supports RAWX and NMEA logging to the SD card. Max logging time can also be set (default is 24 hours) to avoid multi-gigabyte text files. For more information about RAWX and doing PPP please see this tutorial.

Data Port and Digital Mux

The 74HC4052 analog mux controls which digital signals route to the external Data port. This allows a variety of custom end user applications. The most interesting of which is event logging. Because the ZED-F9P has microsecond accuracy of the incoming digital signal, custom firmware can be created to triangulate an event based on the receiver's position and the time delay between multiple captured events. Currently, TM2 event logging is supported.

Additionally, this mux can be configured to connect ESP pin 26 (DAC capable) and pin 39 (ADC capable) for end user custom applications.

Hardware Assembly

The RTK Facet was designed to work with low-cost, off the shelf equipment. Here we’ll describe how to assemble a Rover and Base.

Surveying (Rover Mode)

Shown above is the most common RTK Rover setup. A monopole designed for cameras is used. The ¼” camera thread of the monopole is adapted to ⅝” 11-TPI and the RTK Facet is mounted on top. No radio is needed because RTCM correction data is provided by a phone over Bluetooth.

If you’re shopping for a monopole (aka monopod), get one that is 65” in length or greater to ensure that the antenna will be above your head. We’ve had good luck with the Amazon Basics brand.

If you prefer to mount your tablet or cell phone to the monopole be sure to get a clamp that is compatible with the diameter of your monopole and has a knob to increase clamp pressure. Our monopole is 27mm in diameter so a device clamp would need to be able to handle that diameter.

If you are receiving RTCM correction data over a radio link it’s recommended that you attach a radio to the bottom of the RTK Facet.

Picture hanging strips from 3M make a nice semi-permanent mount. Plug the 4-pin to 6-pin JST cable included with the RTK Facet from the Radio port to either of the Serial Telemetry Radios (shipped in pairs). We really love these radios because they are paired out of the box, either can send or receive (so it doesn't matter which radio is attached to base or rover) and they have remarkable range. We achieved over a mile range (nearly 1.5 miles or 2.4km) with the 100mW radios and a big 915MHz antenna on the base (see this tutorial for more info).

Temporary Base

A temporary or mobile base setup is needed when you are in the field too far away from a correction source and/or cellular reception. A 2nd RTK Facet is mounted to a tripod and it is configured to complete a survey-in (aka, locate itself), then begin broadcasting RTCM correction data. This data (~1000 bytes a second) is sent to the user's connected radio of choice. For our purposes, the 915MHz 100mW telemetry radios are used because they provide what is basically a serial cable between our base and rover.

Any tripod with a ¼” camera thread will work. The Amazon Basics tripod works well enough but is a bit light weight and rickety. The ¼” camera thread is adapted to ⅝” 11-TPI and the RTK Facet is attached on top.

Once the base has been setup with a clear view of the sky, turn on the RTK Facet. Once on, press the Setup button to put the device in Base mode. The display will show the Survey-In screen for 60-120 seconds. Once the survey is complete the display will show the 'Xmitting' display and begin producing RTCM correction data. You can verify this by viewing the LEDs on the telemetry radio (a small red LED will blink when serial data is received from the RTK Facet). The RTK Facet is designed to follow the u-blox recommended survey-in of 60s and a mean 3D standard deviation of 5m of all fixes. If a survey fails to achieve these requirements it will auto-restart after 10 minutes.

Note: A mobile base station works well for quick trips to the field. However, the survey-in method is not recommended for the highest accuracy measurements because the positional accuracy of the base will directly translate to the accuracy of the rover. Said differently, if your base's calculated position is off by 100cm, so will every reading your rover makes. If you’re looking for maximum accuracy consider installing a static base with fixed antenna. We were able to pinpoint the antenna on the top of SparkFun with an incredible accuracy +/-2mm of accuracy using PPP!

Bluetooth and NTRIP

The RTK Facet transmits full NMEA sentences over Bluetooth serial port profile (SPP) at 4Hz and 115200bps. This means that nearly any GIS application that can receive NMEA data over serial port (almost all do) can be used with the RTK Facet. As long as your device can open a serial port over Bluetooth (also known as SPP) your device can retrieve industry standard NMEA positional data. The following steps show how to use SW Maps but the same steps can be followed to connect any serial port based GIS application.

The best mobile app that we’ve found is the powerful, free, and easy to use SW Maps by Softwel. You’ll need an Android phone or tablet with Bluetooth. What makes SW Maps truly powerful is its built-in NTRIP client. This is a fancy way of saying that we’ll be showing you how to get RTCM correction data over the cellular network. If you’re using a serial radio for your correction data, you can skip the later section.

When powered on, the RTK Facet will broadcast itself as either 'Facet Rover-37E2' or 'Facet Base-37E2' depending on which state it is in. Discover and pair with this device from your phone or tablet. Once paired, open SW Maps.

With SW Maps open, click on the blue button in the upper left corner to open the main menu. Select Bluetooth GNSS. This will display a list of available Bluetooth devices. Select the Rover or Base you just paired with. For the Instrument Model drop down select 'SparkFun RTK Surveyor' or 'u-blox RTK' (rather than just 'u-blox'). This is important and will enable the use of NTRIP.

If you are taking height measurements (altitude) in addition to position (lat/long) be sure to enter the height of your antenna off the ground including the ARP offset of the RTK Facet.

The built in antenna has an ARP of 61.4mm from the base to the measuring point of the L1 antenna and an ARP of 57.4mm to the measuring point of the L2 antenna. So if your monopod is 67 inches long fully extended, the antenna offset is 1701.8mm + 61.4mm = 1763mm. You would want to enter 1.763m into SW Maps to get accurate altitude of the point being measured on the ground.

Click on 'CONNECT' to open a Bluetooth connection. Assuming this process takes a few seconds, you should immediately have a location fix.

Next we need to send RTCM correction data back to the RTK Facet so that it can improve its fix accuracy. You can either provide this from the phone or you can use your own radio backhaul (via 915MHz serial radios, cellular, LoRa, etc). We will describe in detail the use of NTRIP and your cellular phone because we find it's the easiest and fastest to get setup.

This is the amazing power of RTK Facet and SW Maps. Your phone can be the radio link! From the main SW Maps menu select NTRIP Client. Not there? Be sure to select 'SparkFun RTK Surveyor' or 'u-blox RTK' instrument when connecting. Disconnect and change the instrument choice to enable the NTRIP Connection option.

Enter your NTRIP caster credentials and click connect. You will see bytes begin to transfer from your phone to the RTK Facet. Within a few seconds the RTK Facet will go from ~300mm accuracy to 14mm. Pretty nifty, no?

What's an NTRIP caster? In a nutshell, it's a server that is sending out correction data every second. There are thousands of sites around the globe that calculate the perturbations in the ionosphere and troposphere that decrease the accuracy of GNSS accuracy. Once the inaccuracies are known, correction values are encoded into data packets in the RTCM format. You, the user, don't need to know how to decode or deal with RTCM, you simply need to get RTCM from a source within 10km of your location into the RTK Facet. The NTRIP client logs into the server (also known as the NTRIP caster) and grabs that data, every second, and sends it over Bluetooth to the RTK Facet.

Don't have access to an NTRIP caster? We have a tutorial for that! Checkout How to Build a DIY GNSS Reference Station. Remember, you can always use a 2nd RTK Facet in Base mode to provide RTCM correction data but it will less accurate than a fixed position caster.

Once you have a full RTK fix you'll notice the location bubble in SW Maps turns to green. Just for fun, rock your rover monopole back and forth on a fixed point. You'll see your location accurately reflected in SW Maps. Millimeter location precision is a truly staggering thing.

Display

The RTK Facet has a 0.96" high-contrast OLED display. While small, it packs various situational data that can be helpful in the field. We will walk you through each display.

Power On/Off

Press and hold the power button until the display illuminates to turn on the device. Similarly, press and hold the power button to turn off the device.

Rover Fix

Upon power up the device will enter either Rover mode or Base mode. Above, the Rover mode is displayed.

• MAC: The MAC address of the internal Bluetooth module. This is helpful knowledge when attempting to connect to the device from your phone. This will change to a Bluetooth symbol once connected.
• HPA: Horizontal positional accuracy is an estimate of how accurate the current positional readings are. This number will decrease rapidly after first power up and settle around 0.3m depending on your antenna and view of the sky. When RTK fix is achieved this icon will change to a double circle and the HPA number will decrease even further to as low as 0.014m.
• SIV: Satellites in view is the number of satellites used for the fix calculation. This symbol will blink before a location fix is generated and become solid when the device has a good location fix. SIV is a good indicator of how good of a view the antenna has. This number will vary but anything above 10 is adequate. We've seen as high as 31.
• Model: This icon will change depending on the selected dynamic model: Portable (default) Pedestrian, Sea, Bike, Stationary, etc.
• Log: This icon will remain animated while the log file is increasing. This is a good visual indication that you have an SD card inserted and RTK Facet can successfully record to it.

Rover RTK Fix

Once NTRIP is enabled on your phone or RTCM data is being streamed into the Radio port the device will gain an RTK Fix. You should see the HPA drop to 14mm with a double circle bulls-eye as shown above.

Base Survey-In

Pressing the Setup button will change the device to Base mode. If the device is configured for Survey-In base mode, a flag icon will be shown and the survey will begin. The mean standard deviation will be shown as well as the time elapsed. For most Survey-In setups, the survey will complete when both 60 seconds have elapsed and a mean of 5m or less is obtained.

Base Transmitting

Once the survey-in is complete the device enters RTCM Transmit mode. The number of RTCM transmissions is displayed. By default this is one per second.

The Fixed Base mode is similar but uses a structure icon (shown above) to indicate a fixed base.

Base Transmitting NTRIP

If the NTRIP server is enabled the device will first attempt to connect over WiFi. The WiFi icon will blink until a WiFi connection is obtained. If the WiFi icon continually blinks be sure to check your SSID and PW for the local WiFi.

Once WiFi connects the device will attempt to connect to the NTRIP mount point. Once successful the display will show 'Casting' along with a solid WiFi icon. The number of successful RTCM transmissions will increase every second.

Note: During NTRIP transmission WiFi is turned on and Bluetooth is turned off. You should not need to know the location information of the base so Bluetooth should not be needed. If necessary, USB can be connected to the USB port to view detailed location and ZED-F9P configuration information.

Output to an Embedded System

Many applications using the RTK Facet will use a 3rd party GIS application or mobile app like SW Maps and receive the data over Bluetooth. Alternatively, for embedded applications a user can obtain the NMEA data over serial directly.

For this example we will connect the output from the Data port to a USB to Serial adapter so that we can view the serial data.

Connect the included 4-pin JST to breadboard cable to the Data port. The cable has the following pinout:

• Red - 3.3V
• Green - TX (output from RTK Facet)
• Orange - RX (input to RTK Facet)
• Black - GND

Open a terminal at 115200bps and you should see NMEA sentences:

The Data connector on the RTK Facet is a 4-pin locking 1.25mm JST SMD connector (part#: SM04B-GHS-TB, mating connector part#: GHR-04V-S). 3.3V is provided by this connector to power a remote device if needed. While the port is capable of sourcing up to 600mA, we do not recommend more than 300mA. This port should not be connected to a power source, so if your embedded device has its own power do not connect the red wire.

The parsing of NMEA sentences is straightforward and left to the reader. There are ample NMEA parsing libraries available in C++, Arduino, python, and many more languages.

System Configuration

The RTK Facet is an exceptional GNSS receiver out-of-box and can be used with little or no configuration. The following information is for advanced setups including advanced survey-in scenarios and post processing RAWX data.

All the following settings are stored both on internal memory and an SD card if one is detected. The RTK Facet will load the latest settings at each power on. If there is a discrepancy between the internal settings and a settings file then the settings file will be used. This allows a group of RTK Facets to be identically configured using one 'golden' settings file loaded onto an SD card.

There are three ways to configure the RTK Facet.

• WiFi - Recommended
• Serial Terminal - Requires a computer but allows for all configuration settings
• Settings File - Error Prone; for very advanced users only.

System Configuration - WiFi

Starting with firmware v1.7, WiFi based configuration is supported and recommended. For more information about updating the firmware on your device, please see Firmware Updates and Customization.

To get into WiFi configuration follow these steps:

1. Power on the RTK Facet.
2. Once the device has started press the Setup button repeatedly until the Config menu is highlighted.
3. The RTK Facet will blink a WiFi icon indicating it is waiting for incoming connections.
4. Connect to WiFi network named ‘RTK Config’.
5. Open a browser (Chrome is preferred) and type 192.168.4.1 into the address bar.

Note: Upon connecting, your phone may warn you that this WiFi network has no internet. That's ok. Stay connected to the network and open a browser.

Clicking on a category 'carrot' will open or close that section. Clicking on an ‘i’ will give you a brief description of the options within that section.

Please note that the firmware for the RTK device and the firmware for the ZED receiver are shown at the top of the page. This can be helpful when troubleshooting or requesting new features.

GNSS Configuration

The ZED-F9P module used in the Facet is immensely configurable. The RTK Facet will, by default, put the ZED-F9P into the most common configuration for rover/base RTK for use with SW Maps. The GNSS Receiver menu allows a user to enable/disable various sentences and options for the ZED-F9P:

• Measurement Frequency
• Dynamic Model
• Constellation Support
• Messages (NMEA Sentences)

Measurement Frequency

By default, the RTK Facet outputs a solution or location 'fix' 4 times a second. This can be increased but anything above 4Hz is not guaranteed to be stable. The Bluetooth buffer can quickly become overwhelmed and/or if datalogging is enabled the system can become bogged down with SD write delays. Decreasing to 1Hz is completely acceptable and will reduce the log sizes significantly.

Note: When in base mode, measurement frequency is set to 1Hz. This is because RTK transmission does not benefit from faster updates, nor does logging of RAWX for PPP.

Dynamic Model

The ZED-F9P uses various models to augment the location fix. Select the model appropriate for your particular application for best performance. The default is Portable.

Constellation Support

The ZED-F9P is capable of tracking 184 channels across four constellations and two bands (L1/L2) including GPS (USA), Galileo (EU), BeiDou (China), and GLONASS (Russia). SBAS (satellite-based augmentation system) is also supported. By fault, all constellations are used. Some users may want to study, log, or monitor a subset. Disabling a constellation will cause the ZED to ignore those signals when calculating a location fix.

Messages

The ZED-F9P supports more than 70 different messages. Some messages, like NMEA, output location information. Other messages report the internal status of the ZED-F9P. Please see the ZED-F9P Integration Manual for more information about specific message types.

Each message rate input controls which messages are disabled (0) and how often the message is reported (1 = one message reported per 1 fix, 5 = one report every 5 fixes). The message rate range is 0 to 20.

The two large buttons at the top allow you to quickly enable the defaults or logging defaults.

NMEA Defaults: By default, the RTK Facet outputs 5 NMEA sentences allowing for connectivity to most GIS applications. These include GxGGA, GxGSA, GxGST, GxGSV, and GxRMC.

Logging Defaults: If you are doing post processing (PPP) for base station creation or study, it is handy to record RAWX and SFRBX messages in addition to the 5 NMEA message. Pressing this button will set the messages accordingly.

Note: All enabled messages are broadcast over Bluetooth and logged (if a microSD card is present and enabled).

Base Configuration

Survey-In

By default, the RTK Facet will enter 'Survey-In' mode when a user presses the POWER/SETUP button and selects 'Base'. The unit will monitor all constellations until both the observation time and required mean 3D standard deviation is met. u-blox recommends 60s and 5m but these are configurable. Please know that setting very long observation times (people have tried 24 hours) and very small means (1m or less) really doesn't get you much. Survey-in is limited in its precision. It's quick (1 minute!) but it's much less precise than a PPP setup.

Fixed Base

A fixed base is where the precise location of a device is known. This is either obtained via PPP or by locating a device on a survey marker. Once ‘Fixed’ is selected a user is able to enter the known position of the antenna in either ECEF or Geographic coordinates. Whenever a user selects 'Base' the GNSS receiver will immediately go into base mode with these coordinates and nearly immediately begin outputting RTCM correction data.

NTRIP Server

The RTK Facet can be configured to transmit its RTCM directly over WiFi to the user's mountpoint. This eliminates the need for a radio link or a cell phone link.

Once the NTRIP server is enabled you will need a handful of credentials:

• Local WiFi SSID and password
• A casting service and port such as RTK2Go or Emlid (the port is almost always 2101)
• A mount point and password

With these credentials set, RTK Facet will attempt to connect to WiFi, then connect to your caster of choice, and then begin transmitting the RTCM data over WiFi. We tried to make it as easy as possible. Every second a few hundred bytes, up to ~2k, will be transmitted to your mount point. Any rover can then connect to this mount point and gain its RTCM correction data over a cellular or internet connection.

Ports Configuration

By default the Radio port is set to 57600bps to match the Serial Telemetry Radios that are recommended to be used with the RTK Facet (it is a plug and play solution). This can be set from 4800bps to 921600bps.

The Data port on the RTK Facet is very flexible. Internally the Data connector is connected to a digital mux allowing one of four software selectable setups. By default the Data port will be connected to the UART1 of the ZED-F9P and output any messages via serial.

• NMEA - The TX pin outputs any enabled messages (NMEA, UBX, and RTCM) at a default of 460,800bps (configurable 9600 to 921600bps). The RX pin can receive RTCM for RTK and can also receive UBX configuration commands if desired.
• PPS/Trigger - The TX pin outputs the pulse-per-second signal that is accurate to 30ns RMS. The RX pin is connected to the EXTINT pin on the ZED-F9P allowing for events to be measured with incredibly accurate nano-second resolution. Useful for things like audio triangulation. See the Timemark section of the ZED-F9P Integration Manual for more information.
• I2C - The TX pin operates as SCL, RX pin as SDA on the I2C bus. This allows additional sensors to be connected to the I2C bus.
• GPIO - The TX pin operates as a DAC capable GPIO on the ESP32. The RX pin operates as a ADC capable input on the ESP32. This is useful for custom applications.

By default the Data port is set to NMEA and 460800bps. It is configurable from 4800bps to 921600bps. The 460800bps baud rate was chosen to support applications where a large number of messages are enabled and a large amount of data is being sent. If you need to decrease the baud rate to 115200bps or other, but be sure to monitor the MON-COMM message within u-center for buffer overruns. A baud rate of 115200bps and the NMEA+RXM default configuration at 4Hz will cause buffer overruns.

If you must run the data port at lower than 460800bps, and you need to enable a large number of messages and/or increase the fix frequency beyond 4Hz, be sure to verify that UART1 usage stays below 99%. The image above shows the UART1 becoming overwhelmed because the ZED cannot transmit at 115200bps fast enough.

Most applications do not need to plug anything into the Data port. Most users will get their NMEA position data over Bluetooth. However, this port can be useful for sending position data to an embedded microcontroller or single board computer. The pinout is 3.3V / TX / RX / GND. 3.3V is provided by this connector to power a remote device if needed. While the port is capable of sourcing up to 600mA, we do not recommend more than 300mA. This port should not be connected to a power source.

System Configuration

Log to SD

If a microSD card is detected, all messages will be logged. Once the max log time is achieved, logging will cease. This is useful for limiting long term, overnight, static surveys to a certain length of time. Default: 1440 minutes (24 hours). Limit: 1 to 2880 minutes.

Enable Factory Defaults

Factory Defaults will erase any user settings and reset the internal receiver to stock settings. Any logs on SD are maintained. To prevent accidental reset the checkbox must first be checked before the button is pressed.

SD Card

Various stats for the SD card are shown. If valid firmware is detected, available firmware files will be shown. The user must select the firmware they would like to update to. To prevent accidental updates the checkbox must first be checked before the button is pressed.

Add Firmware

New firmware may be uploaded via WiFi to the SD card. Firmware is only loaded to the SD card and must then be loaded to the unit.

Reset Counter

A counter is displayed indicating the number of non-power-on-resets since the last power on.

Saving and Exit

Once settings are input, please press ‘Save Configuration’. This will validate any settings, show any errors that need adjustment, and send the settings to the unit. The page will remain active until the user presses ‘Exit to Rover Mode’ at which point the unit will exit WiFi configuration and return to standard Rover mode.

System Configuration - Serial Terminal

Main Menu

To configure the RTK Facet attach a USB C cable to the USB connector. Open a terminal window at 115200bps; you should see various status messages every second. Press any key to open the configuration menu. Not sure how to use a terminal? Checkout our Serial Terminal Basics tutorial.

Pressing any button will display the Main menu. The Main menu will display the current firmware version and the Bluetooth broadcast name. Note: When powered on, the RTK Facet will broadcast itself as either Facet Rover-XXXX or Facet Base-XXXX depending on which state it is in.

The menus will timeout after 15 seconds of inactivity, so if you do not press a key the RTK Facet will return to reporting status messages after 15 seconds.

Configure GNSS Receiver

Pressing 1 will bring up the GNSS Receiver configuration menu. The ZED-F9P is immensely configurable. The RTK Facet will, by default, put the ZED-F9P into the most common configuration for rover/base RTK for use with SW Maps.

The GNSS Receiver menu allows a user to change the report rate, dynamic model, and select which constellations should be used for fix calculations.

Measurement Frequency can be set by either Hz or by seconds between measurements. Some users need many measurements per second; the RTK Facet supports up to 20Hz with RTK enabled. Some users are doing very long static surveys that require many seconds between measurements; RTK Facet supports up to 8255 seconds (137 minutes) between readings.

Note: When in base mode, measurement frequency is set to 1Hz. This is because RTK transmission does not benefit from faster updates, nor does logging of RAWX for PPP.

The Dynamic Model can be changed but it is recommended to leave as Portable. For more information, please refer to the ZED-F9P Integration Manual.

Constellations Menu: The ZED-F9P is capable of tracking 184 channels across four constellations and two bands (L1/L2) including GPS (USA), Galileo (EU), BeiDou (China), and GLONASS (Russia). SBAS (satellite-based augmentation system) is also supported. By fault, all constellations are used. Some users may want to study, log, or monitor a subset. Disabling a constellation will cause the ZED to ignore those signals when calculating a location fix.

Messages Menu

From this menu a user can control the output of various NMEA, RTCM, RXM, and other messages. Any enabled message will be broadcast over Bluetooth and recorded to SD (if available).

Because of the large number of configurations possible, we provide a few common settings:

• Reset to Surveying Defaults (NMEAx5)
• Reset to PPP Logging Defaults (NMEAx5 + RXMx2)
• Turn off all messages
• Turn on all messages

Reset to Surveying Defaults (NMEAx5) will turn off all messages and enable the following messages:

• NMEA-GGA, NMEA-SGA, NMEA-GST, NMEA-GSV, NMEA-RMC

These five NMEA sentences are commonly used with SW Maps for general surveying.

Reset to PPP Logging Defaults (NMEAx5 + RXMx2) will turn off all messages and enable the following messages:

• NMEA-GGA, NMEA-SGA, NMEA-GST, NMEA-GSV, NMEA-RMC, RXM-RAWX, RXM-SFRBX

These seven sentences are commonly used when logging and doing Precise Point Positioning (PPP) or Post Processed Kinematics (PPK). You can read more about PPP here.

Turn off all messages will turn off all messages. This is handy for advanced users who need to start from a blank slate.

Turn on all messages will turn on all messages. This is a setting used for firmware testing and should not be needed in normal use.

As mentioned is the microSD section of the Hardware Overview there are a large number of messages supported. Each message sub menu will present the user with the ability to set the message report rate.

Note: The message report rate is the number of fixes between message reports. In the image above, with GSV set to 4, the NMEA GSV message will be produced once every 4 fixes. Because the device defaults to 4Hz fix rate, the GSV message will appear once per second.

Base

The RTK Facet can also serve as a correction source, also called a Base. The Base doesn't move and 'knows' where it is so it can calculate the discrepancies between the signals it is receiving and what it should be receiving. These differences are the correction values passed to the Rover so that the Rover can have millimeter level accuracy.

There are two types of bases: Surveyed and Fixed. A surveyed base is often a temporary base setup in the field. Called a 'Survey-In', this is less accurate but requires only 60 seconds to complete. The 'Fixed' base is much more accurate but the precise location at which the antenna is located must be known. A fixed base is often a structure with an antenna bolted to the side. Raw satellite signals are gathered for a few hours then processed using Precision Point Position. We have a variety of tutorials that go into depth on these subjects but all you need to know is that the RTK Facet supports both Survey-In and Fixed Base techniques.

The Base Menu allows the user to select between Survey-In or Fixed Base setups.

In Survey-In mode, the minimum observation time and Mean 3D Standard Deviation can be set. The defaults are 60s and 5m as directed by u-blox. Don't be fooled; setting the observation time to 4 hours is not going to significantly improve the accuracy of the survey - use PPP instead.

In Fixed mode, the coordinates of the antenna need to be sent. These can be entered in ECEF or Geographic coordinates. Whenever a user enters Base mode by pressing the SETUP button the GNSS receiver will immediately go into base mode with these coordinates and immediately begin outputting RTCM correction data.

NTRIP Server

NTRIP is where the real fun begins. The Base needs a method for getting the correction data to the Rover. This can be done using radios but that's limited to a few kilometers at best. If you've got WiFi reception, use the internet!

Enabling NTRIP will present a handful of new options seen below:

This is a new and powerful feature of the RTK Facet. The RTK Facet can be configured to transmit its RTCM directly over WiFi to the user's mountpoint. This eliminates the need for a radio link.

Once the NTRIP server is enabled you will need a handful of credentials:

• Local WiFi SSID and password
• A casting service such as RTK2Go or Emlid (the port is almost always 2101)
• A mount point and password

With these credentials set, RTK Facet will attempt to connect to WiFi, your caster of choice, and begin transmitting the RTCM data over WiFi. We tried to make it as easy as possible.

Every second a few hundred bytes, up to ~2k, will be transmitted to your mount point.

Configure Ports Menu

By default the Radio port is set to 57600bps to match the Serial Telemetry Radios that are recommended to be used with the RTK Facet (it is a plug and play solution). This can be set from 4800bps to 921600bps.

By default the Data port is set to 460800bps and can be configured from 4800bps to 921600bps. The 460800bps baud rate was chosen to support applications where a large number of messages are enabled and a large amount of data is being sent. If you need to decrease the baud rate to 115200bps or other, but be sure to monitor the MON-COMM message within u-center for buffer overruns. A baud rate of 115200bps and the NMEA+RXM default configuration at 4Hz will cause buffer overruns.

If you must run the data port at lower than 460800bps, and you need to enable a large number of messages and/or increase the fix frequency beyond 4Hz, be sure to verify that UART1 usage stays below 99%. The image above shows the UART1 becoming overwhelmed because the ZED cannot transmit at 115200bps fast enough.

The Data port on the RTK Facet is very flexible. It can be configured in four different ways:

Internally the Data connector is connected to a digital mux allowing one of four software selectable setups. By default the Data port will be connected to the UART1 of the ZED-F9P and output any messages via serial.

• NMEA - The TX pin outputs any enabled messages (NMEA, UBX, and RTCM) at a default of 460,800bps (configurable 9600 to 921600bps). The RX pin can receive RTCM for RTK and can also receive UBX configuration commands if desired.
• PPS/Trigger - The TX pin outputs the pulse-per-second signal that is accurate to 30ns RMS. The RX pin is connected to the EXTINT pin on the ZED-F9P allowing for events to be measured with incredibly accurate nano-second resolution. Useful for things like audio triangulation. See the Timemark section of the ZED-F9P Integration Manual for more information.
• I2C - The TX pin operates as SCL, RX pin as SDA on the I2C bus. This allows additional sensors to be connected to the I2C bus.
• GPIO - The TX pin operates as a DAC capable GPIO on the ESP32. The RX pin operates as a ADC capable input on the ESP32. This is useful for custom applications.

Most applications do not need to plug anything into the Data port. Most users will get their NMEA position data over Bluetooth. However, this port can be useful for sending position data to an embedded microcontroller or single board computer. The pinout is 3.3V / TX / RX / GND. 3.3V is provided by this connector to power a remote device if needed. While the port is capable of sourcing up to 600mA, we do not recommend more than 300mA. This port should not be connected to a power source.

Configure Data Logging Menu

[

Pressing 5 will enter the Logging Menu. This menu will report the status of the microSD card. While you can enable logging, you cannot begin logging until a microSD card is inserted. Any FAT16 or FAT32 formatted microSD card up to 32GB will work. We regularly use the SparkX brand 1GB cards but note that these log files can get very large (>500MB) so plan accordingly.

• Option 1 will enable/disable logging. If logging is enabled, all messages from the ZED-F9P will be recorded to microSD. A log file is created at power on with the format SFE_Facet_YYMMDD_HHMMSS.txt based on current GPS data/time.
• Option 2 allows a user to set the max logging time. This is convenient to determine the location of a fixed antenna or a receiver on a repeatable landmark. Set the RTK Facet to log RAWX data for 10 hours, convert to RINEX, run through an observation processing station and you’ll get the corrected position with <10mm accuracy. Please see the How to Build a DIY GNSS Reference Station tutorial for more information.

Note: If you are wanting to log RAWX sentences to create RINEX files useful for post processing the position of the receiver please see the GNSS Configuration Menu. For more information on how to use a RAWX GNSS log to get higher accuracy base location please see the How to Build a DIY GNSS Reference Station tutorial.

Configuring ZED-F9P with u-center

Note: Because the ESP32 does considerable configuration of the ZED-F9P at power on it is not recommended to modify the settings of the ZED-F9P. Nothing will break but your changes may be overwritten.

The ZED-F9P module can be configured independently using the u-center software from u-blox by connecting a USB cable to the *Config u-blox’ USB C connector. Settings can be saved to the module between power cycles. For more information please see SparkFun’s Getting Started with u-center by u-blox.

System Configuration - Settings File

Note: All system configuration can also be done by editing the SFE_Facet_Settings.txt file (shown above) that is created when a microSD card is installed. The settings are clear text but there are no safety guards against setting illegal states. It is not recommended to use this method unless You Know What You're Doing®.

Firmware Updates and Customization

The RTK Facet is open source hardware meaning you have total access to the firmware and hardware. Be sure to checkout each repo for the latest firmware and hardware information. But for those who want to jump right in and tweak the firmware, we will discuss various methods.

[

You can check your firmware by opening the main menu by pressing a key at any time.

Updating Firmware From the SD Card

From time to time SparkFun will release new firmware for the RTK Facet to add and improve functionality. For most users, firmware can be upgraded by loading the appropriate firmware file from the binaries repo folder onto the SD card and bringing up the firmware menu as shown above.

The firmware upgrade menu will only display files that have the "RTK_Surveyor_Firmware*.bin" file name format so don't change the file names once loaded onto the SD card. Select the firmware you'd like to load and the system will proceed to load the new firmware, then reboot.

Note: The firmware is called RTK_Surveyor_Firmware_vXX.bin even though this product is called the RTK Facet. We united the different platforms into one. The RTK Firmware runs on all our RTK products.

Updating Firmware From WiFi

Alternatively, firmware may be uploaded via the WiFi AP interface. Currently, the upload process is limited in speed resulting in upload times of nearly 2 minutes. Once the firmware has been uploaded it will be viewable on the firmware list on the page. To prevent accidental loading the Enable Firmware Update checkbox must first be checked before the button is enabled.

Updating Firmware From CLI

The command line interface is also available for more advanced users or users who want to avoid the hassle of swapping out SD cards. You’ll need to download esptool.exe and RTK_Surveyor_Firmware_vXXX_Combined.bin from the repo.

Connect a USB A to C cable from your computer to the ESP32 port on the RTK Facet. Now identify the com port the RTK Enumerated at. The easiest way to do this is to open the device manager:

If the COM port is not showing be sure the unit is turned On. If an unknown device is appearing, you’ll need to install drivers for the CH340. Once you know the COM port, open a command prompt (Windows button + r then type ‘cmd’).

Navigate to the directory that contains the firmware file and esptool.exe. Run the following command:

language:c
esptool.exe --chip esp32 --port COM6 --baud 921600 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size detect 0 RTK_Surveyor_Firmware_v19_combined.bin

Note: You will need to modify COM6 to match the serial port that RTK Facet enumerates at.

Upon completion, your RTK Facet will have the latest and greatest features!

Creating Custom Firmware

The RTK Facet is an ESP32 and high-precision GNSS hackers’s delight. Writing custom firmware can be done using Arduino.

Please see the ESP32 Thing Plus Hookup Guide for information about getting Arduino setup. The only difference is that you will need to select ESP32 Dev Module as your board.

Pull the entire RTK Firmware repo and open /Firmware/RTK_Surveyor/RTK_Surveyor.ino and Arduino will open all the sub-files in new tabs. We’ve broken the functional pieces into smaller tabs to help users navigate it. There are a handful of libraries that will need to be installed. To make this easier, we’ve placed a link next to each library that will automatically open the Arduino Library Manager with that library ready for download.

After connecting a USB C cable to the ESP32 Config connector and selecting the correct COM port you should be able to upload new firmware through the Arduino IDE. Note: The RTK Facet must be turned on for it to enumerate as a COM port.

Troubleshooting

Resources and Going Further

We hope you enjoy using the RTK Facet as much as we have!

Here are the pertinent technical documents for the RTK Facet:

• ZED-F9P GNSS Receiver Datasheet
• MAX17048 Fuel Gauge IC
• SparkFun RTK Facet GitHub Repo (contains the open source hardware electronics and enclosure)
• SparkFun RTK Firmware GitHub Repo (contains the firmware that runs SparkFun RTK products)

Check out these additional tutorials for your perusal:

learn.sparkfun.com | CC BY-SA 3.0 | SparkFun Electronics | Niwot, Colorado

MicroMod Main Board Hookup Guide a learn.sparkfun.com tutorial

Available online at: http://sfe.io/t1994

Introduction

The MicroMod Main Board - Single and Double are specialized carrier boards that allow you to interface a Processor Board with a Function Board(s). The modular system allows you to add an additional feature(s) to a Processor Board with the help of a Function Board(s).

added to your cart!

SparkFun MicroMod Main Board - Single

In stock DEV-18575

The MicroMod Main Board is a specialized carrier board that allows you to interface a MicroMod Processor Board with a single …

$14.95

FavoritedFavorite1

Wish List

added to your cart!

SparkFun MicroMod Main Board - Double

In stock DEV-18576

The MicroMod Main Board is a specialized carrier board that allows you to interface a MicroMod Processor Board with up to two…

$17.95

FavoritedFavorite1

Wish List

Required Materials

To follow along with this tutorial, you will need the following materials at a minimum. You may not need everything though depending on what you have. Add it to your cart, read through the guide, and adjust the cart as necessary.

added to your cart!

SparkFun MicroMod Environmental Function Board

In stock SEN-18632

The MicroMod Environmental Function Board includes three sensors to monitor air quality, humidity / temperature, & CO2 concen…

$149.95

FavoritedFavorite1

Wish List

added to your cart!

SparkFun MicroMod WiFi Function Board - ESP32

In stock WRL-18430

The SparkFun MicroMod ESP32 Function Board adds additional wireless options to MicroMod Processor Boards that do not have tha…

$14.95

FavoritedFavorite1

Wish List

added to your cart!

SparkFun MicroMod Main Board - Single

In stock DEV-18575

The MicroMod Main Board is a specialized carrier board that allows you to interface a MicroMod Processor Board with a single …

$14.95

FavoritedFavorite1

Wish List

added to your cart!

Reversible USB A to C Cable - 2m

In stock CAB-15424

These 2m cables have minor modifications that allow them to be be plugged into their ports regardless of orientation on the U…

$7.95

FavoritedFavorite4

Wish List

added to your cart!

SparkFun MicroMod Artemis Processor

In stock DEV-16401

Featuring the Artemis Module, this processor is capable of machine learning, Bluetooth, I2C, GPIO, PWM, SPI & packaged to fit…

$14.95

FavoritedFavorite8

Wish List

added to your cart!

Pocket Screwdriver Set

In stock TOL-12891

What should every hacker have available to them? That's right, a screwdriver (you have to get into those cases somehow). What…

$3.95

5

FavoritedFavorite19

Wish List

added to your cart!

microSD Card - 1GB (Class 4)

In stock COM-15107

For the times when all you need is a basic SD card this is the card for you. 1GB capacity is plenty to store MP3s or log envi…

$4.95

FavoritedFavorite6

Wish List

MicroMod Main Board

To hold the processor and function boards, you will need one Main board. Depending on your application, you may choose to have either one or two function boards.

added to your cart!

SparkFun MicroMod Main Board - Single

In stock DEV-18575

The MicroMod Main Board is a specialized carrier board that allows you to interface a MicroMod Processor Board with a single …

$14.95

FavoritedFavorite1

Wish List

added to your cart!

SparkFun MicroMod Main Board - Double

In stock DEV-18576

The MicroMod Main Board is a specialized carrier board that allows you to interface a MicroMod Processor Board with up to two…

$17.95

FavoritedFavorite1

Wish List

MicroMod Processor Board

There are a variety of MicroMod Processor Boards available to choose from. You will probably want to avoid having the same Processor and Function Board since there is an ESP32 on both types of boards.

added to your cart!

SparkFun MicroMod Artemis Processor

In stock DEV-16401

Featuring the Artemis Module, this processor is capable of machine learning, Bluetooth, I2C, GPIO, PWM, SPI & packaged to fit…

$14.95

FavoritedFavorite8

Wish List

added to your cart!

SparkFun MicroMod ESP32 Processor

Out of stock WRL-16781

This board combines Espressif's ESP32 with our M.2 connector interface to bring a power-packed processor board into our Micro…

$16.95

FavoritedFavorite5

Wish List

added to your cart!

SparkFun MicroMod SAMD51 Processor

Out of stock DEV-16791

With a 32-bit ARM Cortex-M4F MCU, the SparkFun MicroMod SAMD51 Processor Board is one powerful microcontroller packaged on a …

$18.95

FavoritedFavorite5

Wish List

added to your cart!

SparkFun MicroMod RP2040 Processor

In stock DEV-17720

The SparkFun MicroMod Pi RP2040 Processor Board is a low-cost, high-performance board with flexible digital interfaces featur…

$11.95

FavoritedFavorite6

Wish List

MicroMod Function Board

To add additional functionality to your Processor Board, you'll want to include one or two function boards when connecting them to the Main Board. Make sure to check out the catalog for other function boards.

added to your cart!

SparkFun MicroMod Environmental Function Board

In stock SEN-18632

The MicroMod Environmental Function Board includes three sensors to monitor air quality, humidity / temperature, & CO2 concen…

$149.95

FavoritedFavorite1

Wish List

added to your cart!

SparkFun MicroMod WiFi Function Board - ESP32

In stock WRL-18430

The SparkFun MicroMod ESP32 Function Board adds additional wireless options to MicroMod Processor Boards that do not have tha…

$14.95

FavoritedFavorite1

Wish List

Tools

You will need a screw driver to secure the Processor and Function boards. To set the charge rate, you will need a precision screw driver (or a tiny, rounded object). The pocket screwdriver set is an excellent option. For users using a microSD card and want to easily read the contents of the memory card, you will need a microSD card adapter or USB reader.

added to your cart!

microSD USB Reader

In stock COM-13004

This is an awesome little microSD USB reader. Just slide your microSD card into the inside of the USB connector, then stick t…

$4.95

10

FavoritedFavorite10

Wish List

added to your cart!

Pocket Screwdriver Set

In stock TOL-12891

What should every hacker have available to them? That's right, a screwdriver (you have to get into those cases somehow). What…

$3.95

5

FavoritedFavorite19

Wish List

added to your cart!

SparkFun Mini Screwdriver

In stock TOL-09146

This is just your basic reversible screwdriver - pocket sized! Both flat and phillips heads available. Comes with pin clip an…

$0.95

3

FavoritedFavorite7

Wish List

Suggested Reading

If you aren't familiar with the MicroMod ecosystem, we recommend reading here for an overview. We recommend reading here for an overview if you decide to take advantage of the Qwiic connector.

MicroMod Ecosystem	Qwiic Connect System

If you aren’t familiar with the following concepts, we also recommend checking out a few of these tutorials before continuing. Make sure to check the respective hookup guides for your processor board and function board to ensure that you are installing the correct USB-to-serial converter. You may also need to follow additional instructions that are not outlined in this tutorial to install the appropriate software.

Hardware Overview

The overall functionality of the Single and Double Main Boards are the same. We'll use the Single Main Board more in this section to highlight the features since this is also included in the Double Main Board. We'll switch to the Double Main Board when necessary to highlight the features that are only included in the Double Main Board.

The only differences are that the Double Main Board includes:

• two jumper shunts
• ability to add a second MicroMod Function Board to the mix
• board's width

Main Board - Single Measurements	Main Board - Double Measurements (Zoomed Out)

Power

There are two ways to power the Main Boards, Processor Board, and Function Board(s).

• USB
• Single Cell LiPo Battery

It is fine to connect a power source to the USB connector and LiPo battery's JST connector at the same time. The MicroMod Main Board has power-control circuitry to automatically select the best power source.

Power USB

One option of powering the board is through the USB Type C connector. You will need a USB Type C cable to power the board with 5V. Power connected to the board's USB C connector will go through a resettable PTC fuse (rated at 2A max) and then the AP7361C 3.3V voltage regulator (rated at 1A max). The little green component close to the USB connector is the resettable PTC fuse while the square IC is the voltage regulator. The voltage regulator accepts voltages between ~3.3V to 6.0V.

The USB Type C connector is also used to upload code to your Processor Board, send serial data to a terminal window, or charge the LiPo battery. Of course for portable power, you could connect a USB battery as an alternative to using a LiPo battery.

Power applied to the connector will light up the VIN and 3V3 LED. If you decide to bypass the PTC fuse, simply add a solder blob to the jumper labeled as PTC. There is also a jumper labeled as MEAS to measure the current consumption at the output of the 3.3V voltage regulator for your project.

Power LiPo

The other option is to connect a single cell LiPo battery (i.e. nominal 3.7V, 4.2V fully charged) to the 2-pin JST connector as shown below. A MCP73831 charge IC is included on the boards to safely charge the LiPo batteries via USB Type C connector. A switch is included to set the charge rate. The charge rate is probably set to ~166mA with both switches flipped to the ON position. This may vary depending on the position of the switch when it was pulled from the reel. Flip the switch to adjust the charge rate to either 100mA or 500mA using a precision flat head screw driver or tweezers.

The voltage from the LiPo battery is regulated down to 3.3V as it goes through the AP7361C 3.3V voltage regulator (rated at 1A max).

Note: For more information on proper handling of LiPo batteries, check out the LilyPad Basics: Powering Your Project - LiPo Battery Safety Care.

MicroMod Processor Board

The MicroMod ecosystem allows you to easily swap out processors depending on your application. The location of the M.2 connector labeled as Processor is where you would connect and secure a MicroMod Processor Board.

MicroMod Function Board

Beside the MicroMod Processor's socket is another M.2 connector for MicroMod Function Boards, which allow you to add additional functionality to your Processor Board. The Single Main Board includes one socket for a single Function Board while the Double Main Board includes two sockets for up two Function Boards.

Main Board - Single Function Board Socket	Main Board - Double Function Board Sockets

Reset and Boot Buttons

Each board includes a reset and boot button. There is an additional reset button PTH next to the reset button. Hitting the reset button to restart your Processor Board. Hitting the boot button will put the Processor Board into a special boot mode. Depending on the processor board, this boot pin may not be connected.

SWD Pins

For advanced users, we proke out the 2x5 SWD programming pins. Note that this is not populated so you will need a compatible header and compatible JTAG programmer to connect.

MicroSD Socket

The board includes a microSD socket if your application requires you to log and save data to a memory card. The primary SPI pins (SDO, SDI, SCK, CS0) from your Processor and Function Board are connected to the microSD Socket.

LEDs

There are three LEDs on the board:

• VIN - The VIN LED lights up to indicate when power available from the USB connector.
• 3V3 - The 3V3 LED lights up to indicate when there is a 3.3V available after power is regulated down from the USB connector or LiPo battery.
• CHG - The on-board yellow CHG LED can be used to get an indication of the charge status of your battery. Below is a table of other status indicators depending on the state of the charge IC.
  
  

Jumpers

The following five jumpers are included on both the Single and Double Main Boards.

• MEAS - By default, the jumper is closed and located on the top side of the board. This jumper is used to measure your system's current consumption. You can cut this jumper's trace and connect the PTHs to a ammeter/multimeter to probe the output from the 3.3V voltage regulator. Check out our How to Use a Multimeter tutorial for more information on measuring current.
• PTC - By default, the jumper is open and located on the bottom of the board. For advanced users that know what you are doing, add a solder blob to the jumper to bypass the resettable PTC fuse to pull more than 2A from the USB source.
• 3.3V EN - By default, this jumper is open and located on the bottom of the board. Closing this jumper enables processor control of the 3.3V bus.
• VIN LED - By default, this jumper is closed and located on the bottom of the board. Cut this trace to disable the LED that is connected to the input of the USB
• 3.3V LED - By default, this jumper is closed and located on the bottom of the board. Cut this trace to disable the LED that is connected to the output of the 3.3V voltage regulator.

Main Board - Single Top View Jumpers	Main Board - Single Bottom View Jumpers

Included only on the Double Main Board are two 1x3 male headers with 2-pin jumper shunts to enable the 3.3V voltage regulator for any Function Board connected to Function Zero and Function One using alternative Processor GPIO pins. Since certain processors have limited GPIO and may not be broken out on certain locations, alternative pins have been provided on the board. The ALT PWR EN0 jumper allows users to control the 3.3V voltage regulator on any Function Board that is connected to Function Zero. When the jumper shunt is on the left side toward the 2-pin JST connector, the jumper shunt connects the PWR EN0 to the Processor Board's GPIO G5 pin. Moving the jumper shunt to the other side connects the Processor Board's GPIO G5 pin to Function Board One's GPIO G3 pin.

The ALT PWR EN1 jumper allows users control power from the 3.3V voltage regulator for any Function Board that is connected to Function One when the jumper shunt is connecting PWR EN1 and Processor Board's GPIO G6 pin. Moving the jumper shunt to the other side connects the Processor Board's GPIO G6 pin to Function Board One's GPIO G4 pin.

Qwiic and I²C

The board includes a vertical and horizontal Qwiic connector. These are connected to the primary I²C bus and 3.3V power on both the Processor and Function Board connectors allowing you to easily add a Qwiic-enabled device to your application.

Note that there are two mounting holes for Qwiic-enabled boards that have a standard 1.0"x1.0" size board. The image below highlighted with a black square is where you would place the board.

MicroMod Pinout

Depending on your window size, you may need to use the horizontal scroll bar at the bottom of the table to view the additional pin functions. Note that the M.2 connector pins on opposing sides are offset from each other as indicated by the bottom pins where it says (Not Connected)*. There is no connection to pins that have a "-" under the primary function.

• MicroMod Main Board - Single
• MicroMod Main Board - Double
• MicroMod General Function Board
• MicroMod General Processor Board
• MicroMod General Pin Descriptions

Board Dimensions

The board dimension of the MicroMod Main Board - Single is 2.90" x 3.40" while the MicroMod Main Board - Double is 2.90" x 4.90". Both boards include 5x mounting holes. Four are located on the edge of each board. The fifth mounting hole is located 0.80" away from another mounting hole to mount Qwiic-enabled boards that have the standard 1.0"x1.0" size board.

MicroMod Main Board - Single	MicroMod Main Board - Double

Hardware Hookup

If you have not already, make sure to check out the Getting Started with MicroMod: Hardware Hookup for information on inserting your Processor and Function Boards to the Main Board.

USB

To program and power the Main Board, you will need to insert the USB-C cable into the USB connector. We will leave the other end disconnected when connecting a Processor or Function board to the Main Board.

When the boards are secure, insert the other end to a computer. When you are finished programming the processor, you can use a USB battery via the USB connector or LiPo battery via the JST connector to power the board.

Processor Board

Align the Processor Board's key into its M.2 connector's socket. Insert the board at an angle (~25°), push down, and tighten the screw. In this case, we had the MicroMod Artemis Processor Board secured in the M.2 connector socket. Depending on your application, you may have a different Processor Board.

Function Boards

Align the Function Board's key into its M.2 connector's socket. Insert the board at an angle (~25°), push down, and tighten one of the screw to hold the board down. Attach the second screw on the other side of the board. Once the board is aligned, tighten both screws fully to secure the board. In this case, we had the Environmental Function Board secured in the M.2 connector socket. Depending on your application, you may have a different Function Board.

If you decide to have two function boards attached to the Main Board - Double, we recommend tightening the screw between the two Function Boards first to hold them down before attaching the remaining screws on either side of the Function Boards. In this case, we had the WiFi Function Board and the Environmental Function Board secured in the M.2 connector socket. Depending on your application, you may have different function boards.

Single Cell LiPo Battery

A precision flat head (or a tiny, rounded object) is needed to set the charge rate for your single cell LiPo battery. When the switch is flipped to the ON position on the 500mA side, the charge rate will be 500mA. When the switch is flipped to the ON position on the 100mA side, the charge rate will be 100mA. When the switch is flipped to the ON position on both the 100mA and 500mA sides, the charge rate will be 166mA.

For mobile applications, attach a single cell LiPo battery to the 2-pin JST connector. Attach a USB cable to a USB port or charger when the battery is low to begin charging.

To remove the LiPo battery, you can pull the white JST connector away from the socket while also wiggling the connector side to side using your thumb and index finger.

Note: For more information on proper handling of LiPo batteries, check out the LilyPad Basics: Powering Your Project - LiPo Battery Safety Care.

Qwiic-Enabled Devices

To Qwiic-ly connect I²C devices, simply insert a Qwiic cable between one of the MicroMod Main Board's Qwiic ports and your Qwiic device.

If you need to mount a Qwiic-enabled board to the MicroMod Main Board, you can grab some standoffs and mount a standard Qwiic 1.0"x1.0" sized board using the two mounting holes near the USB Type C connector. Place the standoff between the boards and tighten the screws to mount. The image below used standoffs with built-in threads.

MicroSD Card

With power removed from the board, insert a microSD card (with the pins facing toward the board) into the socket. You'll hear a nice click indicating that the microSD card is locked in place.

To remove, make sure power is off and press the microSD card into the socket to eject. You'll hear a nice click indicating that the card is ready to be removed from the socket.

Software Installation

Arduino Board Definitions and Driver

We'll assume that you installed the necessary board files and drivers for your Processor Board. In this case, we used the MicroMod Artemis Processor Board which uses the CH340 USB-to-serial converter. If you are using a Processor Board, make sure to check out its hookup guide for your Processor Board.

Arduino Examples

Let's go over a few basic examples to get started with the MicroMod Main Board Single and Double. We'll toggle the 3.3V voltage regulator and log data to a microSD card on both boards.

Example 1: MicroMod Main Board - Single Enable Function Board

If you have not already, select your Board (in this case the MicroMod Artemis), and associated COM port. Copy and paste the code below in your Arduino IDE. Hit the upload button and set the serial monitor to 115200 baud.

language:c
/******************************************************************************

  WRITTEN BY: Ho Yun "Bobby" Chan
  @ SparkFun Electronics
  DATE: 10/19/2021
  GITHUB REPO: https://github.com/sparkfun/SparkFun_MicroMod_Main_Board_Single
  DEVELOPMENT ENVIRONMENT SPECIFICS:
    Firmware developed using Arduino IDE v1.8.12

  ========== DESCRIPTION==========
  This example code toggles the Function Board's AP2112 3.3V voltage 
  regulator's enable pin. The Function Boards built-in power LED should blink.
  This example is based on Arduino's built-in Blink Example:

      https://www.arduino.cc/en/Tutorial/BuiltInExamples/Blink

  Note that this example code uses the MicroMod Main Board - Single. The MicroMod
  Main Board - Double routes the PWR_EN# pins slightly different for the
  two function boards. 

  ========== HARDWARE CONNECTIONS ==========
  MicroMod Artemis Processor Board => MicroMod Main Board - Single => Function Board

  Feel like supporting open source hardware?
  Buy a board from SparkFun!
       MicroMod Artemis Processor Board - https://www.sparkfun.com/products/16401
       MicroMod Main Board - Single - https://www.sparkfun.com/products/18575
       MicroMod Environmental Function Board - https://www.sparkfun.com/products/18632

  LICENSE: This code is released under the MIT License (http://opensource.org/licenses/MIT)

******************************************************************************/

/*Define the power enable pins for the processor board with either SDIO_DATA2 or A1.
  Depending on the processor board, the Arduino pin may be different. 

  Note: Certain Processor Boards like the Artemis have SDIO_Data2 and A1 available
        to control the Function Board's voltage regulator. SAMD51, ESP32, and STM32
        Processor Board pins do not have SDIO Data 2, so users will need to reference
        the Processor Pin A1. Below are a few examples. */


//ARTEMIS
#define PWR_EN0 4   //Function Board 0's "PWR_EN0" pin <= MicroMod SDIO_DATA2 => Artemis Processor Board (D4)
//Alternative option that does the same thing. Make sure to just choose one for PWR_EN0
//#define PWR_EN0 35   //Function Board 0's "PWR_EN0" pin <= MicroMod A1 => Artemis Processor Board (A35)

//TEENSY
//#define PWR_EN0 15   //Function Board 0's "PWR_EN0" pin <= MicroMod A1 => Teensy Processor Board (A1)

//SAMD51
//#define PWR_EN0 18   //Function Board 0's "PWR_EN0" pin <= MicroMod A1 => SAMD51 Processor Board (18)



void setup() {
  // initialize the digital pin as an output.
    pinMode(PWR_EN0, OUTPUT);
}



void loop() {
  digitalWrite(PWR_EN0, HIGH); // turn the 3.3V regulator on (HIGH is the voltage level)
  delay(5000);                 // wait for a few seconds to do something with the function boards

  digitalWrite(PWR_EN0, LOW);  // turn the 3.3V regulator off by making the voltage LOW
  delay(5000);                 // wait for a few seconds before turning function boards back on

}

After uploading, take a look at your Function Board's PWR LED. The LED will be on for about 5 seconds and then turn off for another 5 seconds. It will continue to repeat until power is removed from the MicroMod Main Board - Single.

Example 2: MicroMod Main Board - Double Enable Function Boards

If you have not already, select your Board (in this case the MicroMod Artemis), and associated COM port. Copy and paste the code below in your Arduino IDE. Hit the upload button and set the serial monitor to 115200 baud.

language:c
/******************************************************************************

  WRITTEN BY: Ho Yun "Bobby" Chan
  @ SparkFun Electronics
  DATE: 10/19/2021
  GITHUB REPO: https://github.com/sparkfun/SparkFun_MicroMod_Main_Board_Double
  DEVELOPMENT ENVIRONMENT SPECIFICS:
    Firmware developed using Arduino IDE v1.8.12

  ========== DESCRIPTION==========
  This example code toggles the Function Board's AP2112 3.3V voltage
  regulator's enable pin. The Function Boards built-in power LED should blink.
   This example is based on Arduino's built-in Blink Example:

      https://www.arduino.cc/en/Tutorial/BuiltInExamples/Blink

  Note that this example code uses the MicroMod Main Board - Double. The MicroMod
  Main Board - Single routes the PWR_EN0 pin slightly different for the
  function board. 

  ========== HARDWARE CONNECTIONS ==========
  MicroMod Artemis Processor Board => MicroMod Main Board - Double => Function Boards

  Feel like supporting open source hardware?
  Buy a board from SparkFun!
       MicroMod Artemis Processor Board - https://www.sparkfun.com/products/16401
       MicroMod Main Board - Double - https://www.sparkfun.com/products/18576
       MicroMod Environmental Function Board - https://www.sparkfun.com/products/18632

  LICENSE: This code is released under the MIT License (http://opensource.org/licenses/MIT)

******************************************************************************/

/*Define the power enable pins for the processor board with SDIO_DATA2.
  Depending on the processor board, the Arduino pin may be different. 

  Note: Certain Processor Boards like the Artemis have more than one pin available 
        to control the Function Board's voltage regulator (e.g. SDIO_DATA2 and G5).
        SAMD51, ESP32, and STM32 Processor Board pins do not have SDIO Data 2, so
        users will need to reference the Processor Pin G5. Below are a few examples. */

//ARTEMIS
#define PWR_EN0 4    //Function Board 0's "PWR_EN0" pin <= MicroMod SDIO_DATA2 => Artemis Processor Board (D4)  
#define PWR_EN1 26   //Function Board 1's "PWR_EN1" pin <= MicroMod SDIO_DATA1 => Artemis Processor Board (D26)

//Alternative option that does the same thing. Make sure to just choose one for PWR_EN0 and PWR_EN1
//#define PWR_EN0 29   //Function Board 0's "PWR_EN0" pin <= MicroMod G5 => Artemis Processor Board (A29)
//#define PWR_EN1 14   //Function Board 1's "PWR_EN0" pin <= MicroMod G6 => Artemis Processor Board (D14)


//TEENSY
//#define PWR_EN0 39   //Function Board 0's "PWR_EN0" pin <= MicroMod SDIO_DATA2 => Teensy Processor Board (D39)
//#define PWR_EN1 34   //Function Board 1's "PWR_EN1" pin <= MicroMod SDIO_DATA1 => Teensy Processor Board (D34)

//Alternative option that does the same thing. Make sure to just choose one for PWR_EN0 and PWR_EN1
//#define PWR_EN0 45   //Function Board 0's "PWR_EN0" pin <= MicroMod G5 => Teensy Processor Board (45)
//#define PWR_EN1 6   //Function Board 1's "PWR_EN1" pin <= MicroMod G6 => Teensy Processor Board (6)

//Note: The SAMD51, ESP32, and STM32 Processor Board Pins do not have SDIO Data 2 and SDIO Data 1.

//SAMD51
//#define PWR_EN0 7   //Function Board 0's "PWR_EN0" pin <= MicroMod G5 => SAMD51 Processor Board (D7)
//#define PWR_EN1 8   //Function Board 1's"PWR_EN1" pin <= MicroMod G6 => SAMD51 Processor Board (D8)

//ESP32
//#define PWR_EN0  32   //Function Board 0's "PWR_EN0" pin <= MicroMod G5 => ESP32 Processor Board (32)
//#define PWR_EN1  33   //Function Board 1's"PWR_EN1" pin <= MicroMod G6 => ESP32 Processor Board (33)



void setup() {
  // initialize the digital pins as an output.
  pinMode(PWR_EN0, OUTPUT); 
  pinMode(PWR_EN1, OUTPUT);

}



void loop() {

  digitalWrite(PWR_EN0, HIGH); // turn the 3.3V regulator on (HIGH is the voltage level)
  digitalWrite(PWR_EN1, HIGH); // turn the 3.3V regulator on (HIGH is the voltage level)
  delay(5000);                 // wait for a few seconds to do something with the function boards 

  digitalWrite(PWR_EN0, LOW);  // turn the 3.3V regulator off by making the voltage LOW
  digitalWrite(PWR_EN1, LOW);  // turn the 3.3V regulator off by making the voltage LOW
  delay(5000);                 // wait for a few seconds before turning function boards back on

}

After uploading, take a look at the PWR LEDs on the Function Boards. The LEDs will be on for about 5 seconds and then turn off for another 5 seconds. It will continue to repeat until power is removed from the MicroMod Main Board - Double.

Example 3: Reading and Writing to a MicroSD Card

#define SD_CS_PIN SS

//TEENSY
#define SD_CS_PIN 5 // The microSD Card CS pin is D1 for the MicroMod Main Board - Single and Teensy Processor (5). Adjust for your processor if necessary.
//#define SD_CS_PIN 44 // The microSD Card's CS pin is G4 for the MicroMod Main Board - Double and Teensy Processor (44). Adjust for your processor if necessary.

The example below uses the built-in SD Arduino library. The only difference in the code is the CS pin for the microSD card, which you will need to adjust for your processor board (in this case we use the Artemis Processor Board). Make sure to reference your Processor Board's CS pin for either the Main Board - Single (D1) or Main Board - Double (G4).

If you have not already, select your Board (in this case the MicroMod Artemis), and associated COM port. Copy and paste the code below in your Arduino IDE. Hit the upload button and set the serial monitor to 9600 baud.

language:c
/*
  SD Card Read/Write

  This example shows how to read and write data to and from an SD card file
  The circuit:

  SD card attached to SPI bus as follows:

   SD Card  - MicroMod Artemis Processor Board
   -----------------------------------
   COPI/SDO - pin 38
   CIPO/SDI - pin 43
   CLK      - pin 42
   CS       - pin 1 (Main Board - Single) or 28 (Main Board - Double)

  created   Nov 2010
  by David A. Mellis
  modified 9 Apr 2012
  by Tom Igoe

  This example code is in the public domain.

*/

#include <SPI.h>
#include <SD.h>

//ARTEMIS
//const int SD_CS_PIN = 1; // The microSD Card CS pin is D1 for the MicroMod Main Board - Single and Artemis Processor (D1). Adjust for your processor if necessary.
const int SD_CS_PIN = 28; // The microSD Card's CS pin is G4 for the MicroMod Main Board - Double and Artemis Processor (D28). Adjust for your processor if necessary.

File myFile;

void setup() {
  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }


  Serial.print("Initializing SD card...");

  if (!SD.begin(SD_CS_PIN)) {
    Serial.println("initialization failed!");
    while (1);
  }
  Serial.println("initialization done.");

  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  myFile = SD.open("test.txt", FILE_WRITE);

  // if the file opened okay, write to it:
  if (myFile) {
    Serial.print("Writing to test.txt...");
    myFile.println("testing 1, 2, 3.");
    // close the file:
    myFile.close();
    Serial.println("done.");
  } else {
    // if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  }

  // re-open the file for reading:
  myFile = SD.open("test.txt");
  if (myFile) {
    Serial.println("test.txt:");

    // read from the file until there's nothing else in it:
    while (myFile.available()) {
      Serial.write(myFile.read());
    }
    // close the file:
    myFile.close();
  } else {
    // if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  }
}

void loop() {
  // nothing happens after setup
}

If all goes well, you should see the following output if this is the first time writing to the card!

language:bash
Initializing SD card...initialization done.
Writing to test.txt...done.
test.txt:
testing 1, 2, 3.

If you are looking to go the extra mile to see if data was saved, close the Serial Monitor and remove power from the MicroMod Main Board. Eject your microSD card from the socket and insert into a microSD card adapter. Then insert the microSD card into your computer's card reader or USB port. Open the test.txt file in a text editor. You should see an output similar to what you saw in the Serial Monitor after the file was opened as shown below.

language:bash
testing 1, 2, 3.

Besides verifying the data in the file, this step is also useful if you adjust the code to continuously log data in a CSV format. After logging data, you could the open text document in a spreadsheet and graph the values!

More Examples!

Sweet! Now that we know that we can read and write to the microSD card, try exploring the other examples in either the SD or SdFat Arduino libraries. Or check out the following MicroMod tutorials that have a built-in microSD card socket for ideas on data logging. Better yet, try adding a sensor and write some code to log some data!

Looking for more examples with a Function Board? Below are a few Function Board examples from our tutorials that are tagged with MicroMod.

Better yet, try connecting a Qwiic-enabled device to the Main Board's Qwiic connector. Below are a few examples from our tutorials that are tagged with Qwiic.

Troubleshooting

Resources and Going Further

Now that you've successfully got your MicroMod Main Board with a Processor Board, it's time to incorporate it into your own project! For more information, check out the resources below:

• MicroMod Main Board - Single
  • Schematic (PDF)
  • Eagle Files (ZIP)
  • Board Dimensions (PNG)
  • GitHub Hardware Repo
• MicroMod Main Board - Double
  • Schematic (PDF)
  • Eagle Files (ZIP)
  • Board Dimensions (PNG)
  • GitHub Hardware Repo
• SFE Product Showcase

Looking for more inspiration? Check out these other tutorials related to MicroMod.

learn.sparkfun.com | CC BY-SA 3.0 | SparkFun Electronics | Niwot, Colorado

Getting Started with the Raspberry Pi Zero 2 W a learn.sparkfun.com tutorial

Available online at: http://sfe.io/t2220

Introduction

The latest entry into the immensely popular Raspberry Pi Single Board Computer (SBC) catalog, the Raspberry Pi Zero 2 W, provides an upgraded drop-in replacement to the Pi Zero W powered by a quad-core 64-bit Arm Cortex-A53 CPU. This guide highlights the improvements in hardware on the Pi Zero 2 W, how to set it up in a desktop configuration as well as installing and the basics of using the Raspberry Pi OS.

Raspberry Pi Zero 2 W

Out of stock DEV-18713

The Raspberry Pi Zero 2 W is still the Pi you know and love, but at a largely reduced size of only 65mm long by 30mm wide and…

4

FavoritedFavorite10

Wish List