chirpstack_codec.js

// Decode decodes an array of bytes into an object.
//  - fPort contains the LoRaWAN fPort number
//  - bytes is an array of bytes, e.g. [225, 230, 255, 0]
// The function must return an object, e.g. {"temperature": 22.5}
function bin2String(array) {
  return String.fromCharCode.apply(String, array);
}

function bin2HexStr(arr)
 
{
    var str = "";
    for(var i=0; i<arr.length; i++)
    {

       var tmp = arr[i].toString(16);
       if(tmp.length == 1)
       {
           tmp = "0" + tmp;
       }
       str += tmp;
    }
    return str;
}

function Decode(fPort, bytes) 
{
  
// Decode an uplink message from a buffer
// (array) of bytes to an object of fields.
var value=bytes[0]<<8 | bytes[1];
var batV=value/1000;//Battery,units:V
value=bytes[2]<<8 | bytes[3];
if(bytes[2] & 0xFC)
{value |= 0xFFFF0000;}
var tempc=(value/10).toFixed(2);//DS18B20,PB3,units:℃
var adc_ch0=(bytes[4]<<8 | bytes[5])/1000;//PA0,ADC Channel 0,units:V
var digital_IS=(bytes[6] & 0x02)? "H":"L";//PA12，Digital Input Status
var exti_trigger=(bytes[6] & 0x01)? "TRUE":"FALSE";//PB14,GPIO_MODE_IT_FALLING
value=bytes[7]<<8 | bytes[8];
if(bytes[7] & 0xFC)
{value |= 0xFFFF0000;}
var temp_SHT=(value/10).toFixed(2);//SHT20,temperature,units:℃
value=bytes[9]<<8 | bytes[10];
var hum_SHT=(value/10).toFixed(1);//SHT20,Humidity,units:%

return {
BatV:batV,
TempC:tempc,
ADC_CH0V:adc_ch0,
Digital_IStatus:digital_IS,
EXTI_Trigger:exti_trigger,
//TempC_SHT:temp_SHT,
//Hum_SHT:hum_SHT
};
  
  	//var myObj = {"DecodeDataString":"", "DecodeDataHex":""};
  	//myObj.DecodeDataString = tostring;
  	//myObj.DecodeDataHex = toHextring;
	//return myObj;
}