Decoding data from TTN to DataCake

[richwriroo]

I am having trouble decoding data on DataCake

I have it set up on TTN which works great and have set up an integration with DataCake - I tried your decoder from your instructions with DataCake but don't get any correct values for any decoded values. My integration webhook URL from TTN is https://api.datacake.co/integrations/lorawan/tti

Here is the decoder I am using:

`
function Decoder(bytes, port) {
var decoded = {};
// avoid sending Downlink ACK to integration (Cargo)
if (port === 1) {
var lonSign = (bytes[0]>>7) & 0x01 ? -1 : 1;
var latSign = (bytes[0]>>6) & 0x01 ? -1 : 1;

var encLat = ((bytes[0] & 0x3f)<<17)+
             (bytes[1]<<9)+
             (bytes[2]<<1)+
             (bytes[3]>>7);

var encLon = ((bytes[3] & 0x7f)<<16)+
             (bytes[4]<<8)+
             bytes[5];

var hdop = bytes[8]/10;
var sats = bytes[9];

var maxHdop = 2;
var minSats = 5;

// if ((hdop < maxHdop) && (sats >= minSats)) {
// Send only acceptable quality of position to mappers
decoded.latitude = latSign * (encLat * 108 + 53) / 10000000;
decoded.longitude = lonSign * (encLon * 215 + 107) / 10000000;
decoded.altitude = ((bytes[6]<<8)+bytes[7])-1000;
decoded.accuracy = (hdop*5+5)/10
decoded.hdop = hdop;
decoded.sats = sats;
// } else {
// decoded.error = "Need more GPS precision (hdop must be <"+maxHdop+
" & sats must be >= "+minSats+") current hdop: "+hdop+" & sats:"+sats;
// }
return decoded;
}
return null;
}
`

I get something that looks like this when debugging in DataCake:

{ "accuracy": 0.5, "altitude": -1000, "hdop": 0, "latitude": 5.3e-06, "longitude": 1.07e-05, "sats": 0 }

[disk91]

Please give me your original payload (before decodind)
I think this is a payload from a frame w/o gps position (basically full of 0)

[richwriroo]

Hi Paul thanks for your speedy reply - here is a screen grab from TTN - I think you may be right about the payload being zero's - is my config wrong.

[disk91]

You get 00.. when there is no GPS fix
You decoder should bypass this situation.