Hello everyone,
This is my first post on this forum and my first steps into the major rabbithole of LoRa and wonder if I should have done this or not :’)
I have a Dragino LGT-92 have followed various tutorials and the thing is talking to the TTN and I see data coming in the console.
On the serial port I see:
***** UpLinkCounter= 39 *****
TX on freq 868100000 Hz at DR 2
Server_TX_DUTYCYCLE: 30000
txDone
rxTimeOut
rxTimeOut
Roll=226 Pitch=348
South: 52.1393
East: 4.4697
I have setup the decoder for the payload, the data shows up incorrectly for long/lat, battery, pitch/roll are ok.
On TTN console it shows up as:
payload:07F4B100AE980FD600E2015C alarm:false batV:4.054 latitude:-1625.5823 longitude:-1673.252 pitch:3.48 roll:2.26
Function used (from Dragino documentation):
function Decoder(bytes, port) {
// Decode an uplink message from a buffer
// (array) of bytes to an object of fields.
var alarm = bytes[6] & 0x40 ? true : false; //Alarm status
value = ((bytes[6] & 0x3f) << 8) | bytes[7];
var batV = value / 1000; //Battery,units:Volts
value = (bytes[8] << 8) | bytes[9];
if (bytes[8] & 0x80) {
value |= 0xffff0000;
}
var roll = value / 100; //roll,units: °
value = (bytes[10] << 8) | bytes[11];
if (bytes[10] & 0x80) {
value |= 0xffff0000;
}
var pitch = value / 100; //pitch,units: °
var json = {
roll: roll,
pitch: pitch,
batV: batV,
alarm: alarm,
};
var value = (bytes[0] << 16) | (bytes[1] << 8) | bytes[2];
if (bytes[0] & 0x80) {
}
value |= 0xffffff000000;
var value2 = (bytes[3] << 16) | (bytes[4] << 8) | bytes[5];
if (bytes[3] & 0x80) {
}
value2 |= 0xffffff000000;
if (value == 0x0fffff && value2 == 0x0fffff) {
//gps disabled (low battery)
} else if (value === 0 && value2 === 0) {
//gps no position yet
} else {
}
json.latitude = value / 10000; //gps latitude,units: °
json.longitude = value2 / 10000; //gps longitude,units: °
return json;
}
Is it parsing incorrect bytes ?
Next I use Node-RED extensively, so an opportunity to use the TTN nodes (on github the repo shows as archived ? Are the nodes still correct to use?)
The quickstart guide talks about ‘ttn message node’ which does not exist ?
The payload data shows up in Node-red (using the TTN Event node and using # for the event), however, after a while it stops receiving for some unknown reason, payload still shows up in the TTN console.
Resetting the LGT-92 (ATZ) and it starts to talk again in Node-red, can this behaviour be explained ?
The payload itself appears to be encrypted, get something like: YDIpASaFAAADIf8AAV8FExI=
Using the nodejs lora-packet decoder with the nwskey and appskey for decrypting base64, nothing useful comes out of it.
How can I receive readable data in Node-red ?