node-BMM150

Node JS package for the BMM150 magnetometer unit using I2C

BMM150 Class Documentation

Constructor

constructor(busNumber = 1, address = 0x13)

• busNumber: The I2C bus number (default is 1).
• address: The I2C address of the BMM150 sensor (default is 0x13).

Methods

initialize()

Initializes the sensor by setting the power on, reading the chip ID, and setting the operation mode to normal.

async initialize()

setPower(enabled)

Enables or disables the power.

setPower(enabled)

• enabled: true to enable power, false to disable power.

setOperationMode(mode)

Sets the operation mode of the sensor.

setOperationMode(mode)

• mode: Operation mode (e.g., BMM150.OP_MODE_NORMAL).

setPresetMode(mode)

Sets the preset mode for the sensor.

setPresetMode(mode)

• mode: Preset mode (e.g., BMM150.PRESETMODE_HIGHACCURACY).

setRate(rate)

Sets the data rate for the sensor.

setRate(rate)

• rate: Data rate (e.g., BMM150.RATE_10HZ).

setMeasurementXYZ()

Enables measurement on the X, Y, and Z axes.

setMeasurementXYZ()

readMagnetometerData()

Reads the raw magnetometer data from the sensor.

readMagnetometerData()

• Returns an object with x, y, and z properties representing the raw data.

getGeomagnetic()

Gets the compensated geomagnetic data.

getGeomagnetic()

• Returns an object with x, y, and z properties in microteslas (µT).

getCompassDegree()

Gets the compass degree based on geomagnetic data.

getCompassDegree()

• Returns the degree value indicating the angle between the pointing direction and north.

streamLiveData(rate)

Streams live data from the sensor at the specified rate.

async streamLiveData(rate = 100)

• rate: The interval rate in milliseconds (default is 100ms).

stopStream()

Stops the live data stream.

stopStream()

Example Usage

Here’s how to use the different methods to get raw data, geomagnetic data, and compass degree.

Example Script

const BMM150 = require('./path/to/bmm150');

(async () => {
    try {
        const bmm150 = new BMM150(1, 0x13); // Specify the I2C bus and address
        await bmm150.initialize();
        console.log('BMM150 initialized successfully');

        // Setup sensor configuration
        bmm150.setOperationMode(BMM150.OP_MODE_NORMAL);
        bmm150.setPresetMode(BMM150.PRESETMODE_HIGHACCURACY);
        bmm150.setRate(BMM150.RATE_10HZ);
        bmm150.setMeasurementXYZ();

        // Get raw data
        const rawData = bmm150.readMagnetometerData();
        console.log(`Raw Magnetometer Data: X=${rawData.x}, Y=${rawData.y}, Z=${rawData.z}`);

        // Get geomagnetic data
        const geomagneticData = bmm150.getGeomagnetic();
        console.log(`Geomagnetic Data: X=${geomagneticData.x} µT, Y=${geomagneticData.y} µT, Z=${geomagneticData.z} µT`);

        // Get compass degree
        const compassDegree = bmm150.getCompassDegree();
        console.log(`Compass Degree: ${compassDegree.toFixed(2)}°`);

        // Stream live data
        bmm150.streamLiveData(100); // Stream data at 10 Hz (100ms interval)

        // Stop streaming after 10 seconds (example)
        setTimeout(() => bmm150.stopStream(), 10000);
    } catch (error) {
        console.error('Error initializing BMM150:', error);
    }
})();

Explanation

1. Initialization:

   • Initialize the sensor using await bmm150.initialize().

2. Setup Configuration:

   • Set the sensor to normal operation mode, high accuracy preset mode, and 10 Hz data rate.
   • Enable measurement on the X, Y, and Z axes.

3. Get Raw Data:

   • Use readMagnetometerData() to get the raw magnetometer data.

4. Get Geomagnetic Data:

   • Use getGeomagnetic() to get the compensated geomagnetic data in microteslas (µT).

5. Get Compass Degree:

   • Use getCompassDegree() to get the compass degree.

6. Stream Live Data:

   • Use streamLiveData(rate) to start streaming live data at the specified rate.
   • Use stopStream() to stop streaming data.

By following this documentation and example usage, you can easily integrate the BMM150 sensor into your Node.js applications and retrieve different types of data as needed.