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I2C Scanner

With the I2C scanner you can search for all the deviced connected to the I2C bus.
When using on the SODAQ SFF you should see two devices.
The GPS and Accelerometer/Magnetometer are both an I2C device.
The Accelerometer and Magnetometer have their own I2C address, therefor you should see three addresses in output of the scanner.

Arduino sketch

#include <Wire.h>

#define Serial SerialUSB

void setup()
{
  Wire.begin();

  pinMode(GPS_ENABLE, OUTPUT);
  digitalWrite(GPS_ENABLE, HIGH);

  Serial.begin(9600);
  while (!Serial);             // wait for serial monitor
  Serial.println("\nI2C Scanner");
}

void loop()
{
  byte error, address;
  int nDevices;

  Serial.println("Scanning...");

  nDevices = 0;
  for(address = 1; address < 127; address++ )
  {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");

      nDevices++;
    }
    else if (error==4)
    {
      Serial.print("Unknow error at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.println(address,HEX);
    }
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");

  delay(5000);           // wait 5 seconds for next scan
}

Output

The output should look like this:

I2C Scanner
Scanning...
I2C device found at address 0x19  !
I2C device found at address 0x1E  !
I2C device found at address 0x42  !
done
Sensor Address
GPS 0x42
Accelerometer 0x19
Magnetometer 0x1E

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