After hours of trial and error modifying LMIC node I’ve managed to get my first temperature sensor (2x DS18B20) node working with TTN albeit postive temperatures work great. However when it comes to negative temperatures I’m stuck… having read several comments here and elsewhere on the net I was act…

Use an offset, so you add 100 or some such number (so that can go down to -100) to your temp: uint16_t tempInt = (uint16_t) ((temp + 100.0) * 100.0); and at the other end: var temp = ( (bytes[0] << 8) + bytes[1]) / 100 ) - 100; So -10.54C becomes 89.46 becomes 8946 and is reversed to 89.46, …

Thank you Nick, that’s very helpful indeed! I had convinced myself my coding inability was at fault and I was clearly missing some clever coding tricks when the the answer, infact, could be reached with some basic maths :man_facepalming:

read this post but rené post will get you there [image] Payload Formats [HowTo] Application Development It’s JavaScript (ECMAScript 5) indeed . For uplinks: Decoder is a JavaScript function that accepts the payload as byte array and returns an object containing the deco…

Thank you both for the replies after a bit more trial and error I’ve got it working as expected. Lesson learnt… don’t get bogged down with the complicated stuff and overlook the simple things :man_facepalming:

[image] paule99: don’t get bogged down with the complicated stuff and overlook the simple things Or just ask nicely with some evidence of prior effort - just like you did - always a pleasure to help people with that next step when they’ve got snow-blind - happens to me all the time!

Payload, Uplink payload formatter & Negative Temperatures

End Devices (Nodes) LMIC

Piet_Pillay (Piet Pillay) December 8, 2023, 4:37pm 4

read this post

but rené post will get you there

hope i am quoting the correct one