http://wiki.dragino.com/xwiki/bin/view/Main/User%20Manual%20for%20LoRaWAN%20End%20Nodes/LDDS75%20-%20LoRaWAN%20Distance%20Detection%20Sensor%20User%20Manual/


Value, Size (bytes)
Battery (mV), 2
Distance (mm), 2
Interrupt, 1
Temperature, 2
Status, 1


payload = 'DQYCjAAAAAE='
frame = base64.b64decode(payload)

battery = struct.unpack('<H', frame[0:2])[0]
distance = struct.unpack('<H', frame[2:4])[0]
interrupt: frame[4:5]
temperature: frame[5:7]
status: struct.unpack('<H', frame[7:8])[0]