bt-sensors-plugin-sk/sensor_classes/SwitchBotMeterPlus.js

Bluetooth Sensors for Signalk -- support for Victron devices, RuuviTag, Xiaomi, ATC and Inkbird, Ultrasonic wind meters, Mopeka tank readers, Renogy Battery and Solar Controllers, Aranet4 environment sensors, SwitchBot temp and humidity sensors, Kilovault

const BTSensor = require("../BTSensor");
class SwitchBotMeterPlus extends BTSensor{
    
    constructor(device, config={}){
        super(device,config)
        if (config.parser){
            this.parser=config.parser
        }
    }

    static ID = 0x0969
    static serviceDataKey = "0000fd3d-0000-1000-8000-00805f9b34fb"
    static modelID = 0x69

    static async  identify(device){
        const md = await this.getDeviceProp(device,'ManufacturerData')
        const sd = await this.getDeviceProp(device,'ServiceData')

        if (!md) return null 
        if (!sd) return null

        const sdKeys = Object.keys(sd)
        const keys = Object.keys(md)
        if ( (keys && keys.length>0) && (sdKeys && sdKeys.length >0) ){
            const id = keys[keys.length-1]
            if (parseInt(id)==this.ID && md[id][0]==modelID && sdKeys[0] == this.serviceDataKey)
               return this
        }
        return null

    }

    async init() {
        await super.init()
        this.initMetadata()
    }

    initMetadata(){

// Apply positive/negative (Byte[4] & 0x80), and convert from deg F if selected (Byte[5] & 0x80) Then convert to deg Kelvin
// Refer https://github.com/OpenWonderLabs/SwitchBotAPI-BLE/blob/latest/devicetypes/meter.md#(new)-broadcast-message 
 
        this.addMetadatum('temp','K', 'temperature', 
            (buffer)=>{return (( ( ( (buffer[4] & 0x7f) + ((buffer[3] & 0x0f)/10) ) * ( (buffer[4] & 0x80)>0 ? 1 : -1 ) ) - ( (buffer[5] & 0x80)>0 ? 32 : 0) ) / ( (buffer[5] & 0x80)>0 ? 1.8 : 1) ) + 273.15 
        })
        this.addMetadatum('humidity','ratio', 'humidity', 
            (buffer)=>{return (buffer[5] & 0x7F)/100    
        })
        this.addMetadatum('battery','ratio', 'Battery Strength', (buffer)=>{return buffer[2]/100})
    }

    propertiesChanged(props){
        super.propertiesChanged(props)    
        const buff = this.getServiceData("0000fd3d-0000-1000-8000-00805f9b34fb")
        if (!buff)
            throw new Error("Unable to get service data for "+this.getDisplayName())
        this.emitData("temp", buff)
        this.emitData("humidity", buff)
        this.emitData("battery", buff)
        
    }                    
    getManufacturer(){
        return "Wonder Labs"
    }

    getName() {
        return "SwitchBotMeterPlus"
    }

}
module.exports=SwitchBotMeterPlus