Access Xiaomi Mijia Temperature/Humidity Sensor via Bluetooth LE (macchina.io)

mijia.js

var sensorRef = serviceRegistry.findByName('io.macchina.btle.peripheral.58:2D:34:35:D7:1D');
var sensor = sensorRef.instance();

const CHAR_BATTERY_LEVEL = 0x0018; // characteristic for reading battery level (0-99)
const CHAR_NOTIFICATION = 0x0010;  // characteristic for enabling temperature/humidity notifications

console.log('connecting...');

function parseValue(str)
{
    var parts = str.split('=');
    if (parts.length == 2)
        return parseFloat(parts[1]);
    else
        return 0.0;
}

sensor.on('connected', ev => {

    console.log('connected');

    sensor.on('notificationReceived', function(ev) {
        var values = ev.data.data.decodeString();
        // "T=25.2 H=52.2"
        var parts = values.split(' ');
        if (parts.length == 2)
        {
            var temp = parseValue(parts[0]);
            var hum  = parseValue(parts[1]);
            console.log('Temperature: %f C, Humidity: %f %', temp, hum);
        }

    });

    console.log('manufacturerName: %s', sensor.manufacturerName());
    console.log('modelNumber:      %s', sensor.modelNumber());
    console.log('serialNumber:     %s', sensor.serialNumber());
    console.log('hardwareRevision: %s', sensor.hardwareRevision());
    console.log('firmwareRevision: %s', sensor.firmwareRevision());
    var battery = sensor.readUInt8(CHAR_BATTERY_LEVEL);
    console.log('battery = %d', battery);
    sensor.writeInt16(CHAR_NOTIFICATION, 0x0001);
});

sensor.on('disconnected', ev => {
    console.log('disconnected');

    setTimeout(() => {
        sensor.connectAsync();
    }, 5000);
});

sensor.on('error', ev => {
   console.error(ev.data);
});

sensor.connectAsync();