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

mijia_btle.js

const GAP_SERVICE_ID = 0x1800;
const BATTERY_SERVICE_ID = 0x180F;
const DEVICE_NAME_CHAR_ID = 0x2A00;
const BATTERY_LEVEL_CHAR_ID = 0x2A19;
const CLIENT_CHAR_CONF_DESCR_ID = 0x2902;
const DEVICE_ADDRESS = '58:2D:34:35:D7:1D';
const ENV_SENSORS_SERVICE_UUID = '226c0000-6476-4566-7562-66734470666d';
const ENV_SENSORS_CHAR_UUID = '226caa55-6476-4566-7562-66734470666d';


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


const pmRef = serviceRegistry.findByName('io.macchina.btle.peripheralmanager');
let pm;
if (pmRef)
{
    pm = pmRef.instance();
    const peripheralName = pm.findPeripheral(DEVICE_ADDRESS); 
    const peripheralRef = serviceRegistry.findByName(peripheralName);
    const peripheral = peripheralRef.instance();

    peripheral.on('connected', ev => {
        console.log('Peripheral connected: %s', peripheral.address());
        console.log('Device Name       : %s', peripheral.deviceName());
        console.log('Manufacturer Name : %s', peripheral.manufacturerName());
        console.log('Model Number.     : %s', peripheral.modelNumber());
        console.log('Hardware Revision : %s', peripheral.hardwareRevision());
        console.log('Firmware Revision : %s', peripheral.firmwareRevision());
        //console.log('Software Revision : %s', peripheral.softwareRevision());
        
        const serviceUUIDs = peripheral.services();
        for (const serviceUUID of serviceUUIDs)
        {
            console.log('Service: %s', serviceUUID);
            const charUUIDs = peripheral.characteristics(serviceUUID);
            {
                for (const charUUID of charUUIDs)
                {
                    const char = peripheral.characteristic(serviceUUID, charUUID);
                    console.log('Characteristic %s: %O', charUUID, char);
                }
            }
        }
        
        const gaUUID = peripheral.serviceUUIDForAssignedNumber(GAP_SERVICE_ID);
        if (!gaUUID.isNull())
        {
            const dnChar = peripheral.characteristicForAssignedNumber(gaUUID, DEVICE_NAME_CHAR_ID);
        
            const deviceName = peripheral.readString0(dnChar.valueHandle);
            console.log('DEVICE NAME: %s', deviceName);
        }
        
        const batUUID = peripheral.serviceUUIDForAssignedNumber(BATTERY_SERVICE_ID);
        if (!batUUID.isNull())
        {
            const batChar = peripheral.characteristicForAssignedNumber(batUUID, BATTERY_LEVEL_CHAR_ID);
            const level = peripheral.readUInt8(batChar.valueHandle);
            console.log('BATTERY LEVEL: %d', level);
        }
        
        const descHandle = peripheral.handleForDescriptor(ENV_SENSORS_SERVICE_UUID, ENV_SENSORS_CHAR_UUID, peripheral.expandUUID(CLIENT_CHAR_CONF_DESCR_ID));
        
        peripheral.on('notificationReceived', ev => {
            const values = ev.data.data.decodeString();
            // "T=25.2 H=52.2"
            const parts = values.split(' ');
            if (parts.length == 2)
            {
                const temp = parseValue(parts[0]);
                const hum  = parseValue(parts[1]);
                console.log('Temperature: %f C, Humidity: %f %', temp, hum);
            }
        });
        peripheral.writeInt16(descHandle, 1);
    });
    

    peripheral.on('disconnected', ev => {
        console.log('Peripheral disconnected: %s', ev.source.address());
    });

    peripheral.connectAsync();
}