Raspberry Pi and HMC5883L magnetometer Java example

The Honeywell HMC5883L is a surface-mount, multi-chip module designed for low-field magnetic sensing with a digital interface for applications such as lowcost compassing and magnetometry. The HMC5883L includes our state-of-theart, high-resolution HMC118X series magneto-resistive sensors plus an ASIC containing amplification, automatic degaussing strap drivers, offset cancellation, and a 12-bit ADC that enables 1° to 2° compass heading accuracy. The I2C serial bus allows for easy interface. The HMC5883L is a 3.0×3.0x0.9mm surface mount 16-pin leadless chip carrier (LCC).

Applications for the HMC5883L include Mobile Phones, Netbooks, Consumer Electronics, Auto Navigation Systems, and Personal Navigation Devices.

The HMC5883L utilizes Honeywell’s Anisotropic Magnetoresistive (AMR) technology that provides advantages over other magnetic sensor technologies. These anisotropic, directional sensors feature precision in-axis sensitivity and linearity. These sensors’ solid-state construction with very low cross-axis sensitivity is designed to measure both the direction and the magnitude of Earth’s magnetic fields, from milli-gauss to 8 gauss. Honeywell’s Magnetic Sensors are among the most sensitive and reliable low-field sensors in the industry

HMC5883L

Parts List

Connection

Code

[codesyntax lang=”java”]

// Distributed with a free-will license.
// Use it any way you want, profit or free, provided it fits in the licenses of its associated works.
// HMC5883
// This code is designed to work with the HMC5883_I2CS I2C Mini Module available from ControlEverything.com.
// https://www.controleverything.com/content/Compass?sku=HMC5883_I2CS#tabs-0-product_tabset-2#tabs-0-product_tabset-2

import com.pi4j.io.i2c.I2CBus;
import com.pi4j.io.i2c.I2CDevice;
import com.pi4j.io.i2c.I2CFactory;
import java.io.IOException;

public class HMC5883
{
	public static void main(String args[]) throws Exception
	{
		// Create I2C bus
		I2CBus Bus = I2CFactory.getInstance(I2CBus.BUS_1);
		// Get I2C device, HMC5883 I2C address is 0x1E(30)
		I2CDevice device = Bus.getDevice(0x1E);

		// Select Configuration register A
		// Normal measurement configuration, data rate o/p = 0.75 Hz 
		device.write(0x00, (byte)0x60);
		// Select Mode register
		// Continuous measurement mode
		device.write(0x02, (byte)0x00);
		Thread.sleep(500);

		// Read 6 bytes of data from 0x03(3)
		// xMag msb, xMag lsb, zMag msb, zMag lsb, yMag msb, yMag lsb
		byte[] data = new byte[6];
		device.read(0x03, data, 0, 6);

		// Convert the data
		int xMag = ((data[0] & 0xFF) * 256 + (data[1] & 0xFF));
		if(xMag > 32767)
		{
			xMag -= 65536;
		}

		int zMag = ((data[2] & 0xFF) * 256 + (data[3] & 0xFF));
		if(zMag > 32767) 
		{
			zMag -= 65536;
		}

		int yMag = ((data[4] & 0xFF) * 256 + (data[5] & 0xFF));
		if(yMag > 32767) 
		{
			yMag -= 65536;
		}

		// Output data to screen
		System.out.printf("Magnetic field in X-Axis : %d %n", xMag);
		System.out.printf("Magnetic field in Y-Axis : %d %n", yMag);
		System.out.printf("Magnetic field in Z-Axis : %d %n", zMag);
	}
}

[/codesyntax]

$> sudo pi4j HMC5883.java

Run the java program.

$> sudo pi4j HMC5883

Output