add radar support

docs/decoding.txt

@@ -1,3 +1,5 @@
+Ultraschall - LDDS75
+
 http://wiki.dragino.com/xwiki/bin/view/Main/User%20Manual%20for%20LoRaWAN%20End%20Nodes/LDDS75%20-%20LoRaWAN%20Distance%20Detection%20Sensor%20User%20Manual/
 
 
@@ -22,3 +24,32 @@ status = struct.unpack('?', frame[7:8])[0]
 print(f"{battery=}, {distance=}, {status=}")
 
 payload = 'DRgAAAAAAAE='
+
+
+
+
+Radar - LMDS200
+
+http://wiki.dragino.com/xwiki/bin/view/Main/User%20Manual%20for%20LoRaWAN%20End%20Nodes/LMDS200%20-%20LoRaWAN%20Microwave%20Radar%20Distance%20%20Sensor%20User%20Manual/
+
+
+Value, Size (bytes), FPORT = 2
+Battery (mV), 2
+Distance 1 (cm), 2
+Distance 2 (cm), 2
+Status, 1
+
+
+import base64
+import struct
+
+payload = 'DN4AqQD8AA=='
+frame = base64.b64decode(payload)
+
+battery = struct.unpack('>H', frame[0:2])[0]
+distance1 = struct.unpack('>H', frame[2:4])[0]
+distance2 = struct.unpack('>H', frame[4:6])[0]
+
+print(f"{battery=}, {distance1=}, {distance2=}")
+
+