[solved] Transmit Failure after days using LMIC library and Arduino IDE

End Devices (Nodes) LMIC
1

Good morning,

I am currently stuck with troubleshooting the transmission failure of my sensor node. It can work for several days fine until it reports a failure detected by the LMIC library and stops transmitting. I am using Arduino IDE, ATMEGA328P and an external interrupt to wake up my sensor node after a certain time interval.

For troubleshooting, I have logged the events using an SD card and noticed following error msg:

Measurement done
23:40:18
Sending uplink packet...
FAILURE

The failure arises from the LMIC library and most likely this part:

// start transmitter (buf=LMIC.frame, len=LMIC.dataLen)
static void starttx () {
ASSERT( (readReg(RegOpMode) & OPMODE_MASK) == OPMODE_SLEEP );
if(getSf(LMIC.rps) == FSK) { // FSK modem
txfsk();
} else { // LoRa modem
txlora();
}
// the radio will go back to STANDBY mode as soon as the TX is finished
// the corresponding IRQ will inform us about completion.
}

The assert function checks the statement and reports an error. How do you think shall I troubleshoot this problem?

I have thought about:

  1. editing the library to report no failures
  2. changing the code flow to allow
  3. best solution imo: add an if statement in the Arduino code to force sleep or restart the loop after detecting a failure.

Thank you!

2

I choose option 1 :upside_down_face:

  • update
    ’ add an if statement in the Arduino code to force sleep after detecting a failure.

option 3 is also promising … but I have to test this first, when the results are in I’ll get back to you.

3

Which LMIC library are you using?

I’ve got devices tested on 50,000 plus transmits with no issues on ATMEGA328P - there must be an reason your getting issues

4

Are you using ADR and linkcheck?
I’m alos having issues currently, my device stops sending after a couple of hour for no aparent reason, and if i disable linkcheck it works ok…
I’m trying to troubleshoot but without any success untill now.

5

Can you share with us your settings? Are you using ADR?

6

Hi Guys, thank you for all your helpful comments. I’ve used the LMIC library by IBM. To my knowledge, there is even a more recent one for Arduino IDE.

The problem was solved codewise by just forcing the MCU to sleep after a transmit failure has been reported.

1 Like
7

good to see you’ve solved it :sunglasses: