Example Code for Arduino-Get geomagnetic data & compass angle

Hardware Preparation

• FireBeetle ESP32-E IoT Microcontroller(SKU: DFR0654) (or similar) x 1
• BMM150 Triple Axis Magnetometer (SKU: SEN0529)x 1
• Gravity-4P I2C/UART Sensor Cable(included with SEN0529) × 1
• Dupont Wires

Software Preparation

• Download Arduino IDE: Click to download Arduino IDE
• Install SDK: click to enter FireBeetle ESP32-E IoT Microcontroller Wiki for SDK installation tutorial
• Download the DFRobot_BMM150 Library: DFRobot_BMM150 Library.
• For Arduino IDE V1.8.19 (or earlier), install the library manually: How to Add a Library
• For Arduino IDE V2.0.0 (or later), directly search for the "DFRobot_BMM150 Library" in the Library Manager and install it.

Wiring Diagram

Other Preparation Work

Ensure the I2C address of the BMM150 sensor is set correctly using the 2-bit DIP switch. The default I2C address is 0X13 (A0=1, A1=1). Refer to the Pinout section for I2C address combinations.

Sample Code

#include "DFRobot_BMM150.h"

DFRobot_BMM150_I2C bmm150(&Wire, I2C_ADDRESS_4);

/*i2c Address select, that CS and SDO pin select 1 or 0 indicates the high or low respectively. There are 4 combinations: 
 *I2C_ADDRESS_1 0x10  (CS:0 SDO:0)
 *I2C_ADDRESS_2 0x11  (CS:0 SDO:1)
 *I2C_ADDRESS_3 0x12  (CS:1 SDO:0)
 *I2C_ADDRESS_4 0x13  (CS:1 SDO:1) default i2c address */

//When using SPI communication, use the following program to construct an object by DFRobot_BMM150_SPI

#define BMM150_CS D3


//DFRobot_BMM150_SPI bmm150(/*cs = */BMM150_CS);

void setup() 
{
  Serial.begin(115200);
  while(!Serial);
  while(bmm150.begin()){
    Serial.println("bmm150 init failed, Please try again!");
    delay(1000);
  } Serial.println("bmm150 init success!");

  bmm150.setOperationMode(BMM150_POWERMODE_NORMAL);//Normal mode

  bmm150.setPresetMode(BMM150_PRESETMODE_HIGHACCURACY);//High-accuracy mode

  bmm150.setRate(BMM150_DATA_RATE_10HZ);//10HZ

  bmm150.setMeasurementXYZ();//Default config of X-, Y-, and Z-axis
}

void loop()
{
  sBmm150MagData_t magData = bmm150.getGeomagneticData();
  Serial.print("mag x = "); Serial.print(magData.x); Serial.println(" uT");
  Serial.print("mag y = "); Serial.print(magData.y); Serial.println(" uT");
  Serial.print("mag z = "); Serial.print(magData.z); Serial.println(" uT");
  
  /* float type data*/
  //Serial.print("mag x = "); Serial.print(magData.xx); Serial.println(" uT");
  //Serial.print("mag y = "); Serial.print(magData.yy); Serial.println(" uT");
  //Serial.print("mag z = "); Serial.print(magData.zz); Serial.println(" uT");
  float compassDegree = bmm150.getCompassDegree();
  Serial.print("the angle between the pointing direction and north (counterclockwise) is:");
  Serial.println(compassDegree);
  Serial.println("--------------------------------");
  delay(100);
}

Result

Burn sample code, and serial prints the geomagnetic data and compass angle obtained by the sensor.