Encoding message sent to TTN

[kriistobal (Cristobal)]

Hi folks i have a question and i’m a newbie with this lorawan stuff.

To put in context, i’m programming the heltec wireless stick board with the ESP-IDF framework and i use a component (ttn from manuelbl) for the connection to ttn. i also have an ug65 gateway from milesight.

I send the following string “102100 2.4 21.3” which are pressure, altitude and temperature respectively. But in ttn i get “31 30 32 31 30 30 30 20 32 2e 34 20 32 31 2e 33”.

My question is who does the encoding of the message to bytes so that it appears like this in ttn? and if there is another more optimal way to encode it before sending it?

[Jeff-UK]

@kriistobal

I send the following string

Not very efficient use of the airwaves - search TTN Forum for “working with bytes” & check out the TTN Docs (ignore banner - works for V3 as much as old V2!) https://www.thethingsnetwork.org/docs/devices/bytes/

Also a text string is typically ASCII - look again at your output from TTN (as HEX) and follow the numbers (pairs) (Unicode would actually be worse needing 3 bytes/character!) https://www.techonthenet.com/ascii/chart.php

[Johan_Scheepers]

There are a few extent post on working with bytes and how you should send your data over LoRaWAN.

If you encode your data to hex and decode, you save a lot on air time and battery life.

If you search the forum lots of recourses.

Decrypting messages for dummies

Thank you a lot, you have really clarified some basic facts. For this purpose is LoraEncoder function - for example to change measured value to number representation of this value, isn’t it? To be sure that this is the right way: way from measured Temp=23.45 to 0x09 0x29 on the TTN Application data page with as small payload as it possible is (from Arduino): float Temp = 23.45; LoraEncoder encoder(buffer); encoder.writeTemperature(Temp); LMIC_setTxData2(1, buffer, strlen((char *)buffer), 0)…