Milesight EM400-MUD: LoRaWAN Ultrasonic Distance Sensor

function decodeUplink(input) {
  var bytes = input.bytes;
  var data = {};

  for (var i = 0; i < bytes.length; ) {
    var channel = bytes[i++];
    var type = bytes[i++];

    if (channel === 0x01 && type === 0x75) {          // battery (%)
      data.battery = bytes[i]; i += 1;
    } else if (channel === 0x03 && type === 0x67) {   // temperature (°C)
      data.temperature = readInt16LE(bytes, i) / 10; i += 2;
    } else if (channel === 0x04 && type === 0x82) {   // distance (mm)
      data.distance = readUInt16LE(bytes, i); i += 2;
    } else if (channel === 0x05 && type === 0x00) {   // position
      data.position = bytes[i] === 1 ? "tilt" : "normal"; i += 1;
    } else if (channel === 0x83 && type === 0x67) {   // temperature with alarm
      data.temperature = readInt16LE(bytes, i) / 10;
      data.temperature_alarm = bytes[i + 2] === 1 ? "alarm" : "release"; i += 3;
    } else if (channel === 0x84 && type === 0x82) {   // distance with alarm
      data.distance = readUInt16LE(bytes, i);
      data.distance_alarm = bytes[i + 2] === 1 ? "alarm" : "release"; i += 3;
    } else {
      break;
    }
  }
  return { data: data };
}

function readUInt16LE(b, i) {
  return ((b[i + 1] << 8) | b[i]) & 0xffff;
}
function readInt16LE(b, i) {
  var v = readUInt16LE(b, i);
  return v > 0x7fff ? v - 0x10000 : v;
}