Use the micro:bit magnetometer with the Arduino IDE

Freescale’s MAG3110 is a small, low-power, digital 3-axis magnetometer. The device can be used in conjunction with a 3-axis accelerometer to realize an orientation independent electronic compass that can provide accurate heading information. It features a standard I2C serial interface output and smart embedded functions.

The MAG3110 is capable of measuring magnetic fields with an output data rate (ODR) up to 80 Hz; these output data rates correspond to sample intervals from 12.5 ms to several seconds. The MAG3110 is available in a plastic DFN package and it is guaranteed to operate over the extended temperature range of -40°C to +85°C.

You have a micro:bit so you already have one on the board

Code

You need to import the Sparkfun library for the MAG3110 to run this example – https://github.com/sparkfun/SparkFun_MAG3110_Breakout_Board_Arduino_Library/archive/master.zip

Source code

#include <SparkFun_MAG3110.h>
 
MAG3110 mag = MAG3110();
 
void setup() 
{
  Serial.begin(9600);
  mag.initialize(); //Initializes the mag sensor
  mag.start();      //Puts the sensor in active mode
}
 
void loop() {
 
  int x, y, z;
  //Only read data when it's ready
  if(mag.dataReady()) 
  {
    //Read the data
    mag.readMag(&x, &y, &z);
 
    Serial.print("X: ");
    Serial.print(x);
    Serial.print(", Y: ");
    Serial.print(y);
    Serial.print(", Z: ");
    Serial.println(z);
 
    Serial.println("--------");
    delay(1000);
  }
}

Testing

Open the serial monitor and move your micro:bit through the various axis, you should see something like this

X: 218, Y: 65109, Z: 65274
——–
X: 71, Y: 64965, Z: 49
——–
X: 598, Y: 65036, Z: 248
——–
X: 423, Y: 65338, Z: 564
——–
X: 348, Y: 61, Z: 565
——–
X: 413, Y: 65532, Z: 576
——–
X: 502, Y: 65024, Z: 65352