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mruijter / lora_transceiver

A lora transceiver for peer to peer communication with the Raspberry PI dragino Lora GPS hat.
MIT License
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Huge packet loss #2

Closed Michael-List closed 5 years ago

Michael-List commented 5 years ago

Hi,

I have an Arduino MKR 1300 which sends weather data (see this code) via lora. If i use my RaspberryPi with the Dragino hat with the original dragino code the RaspberryPi receives nearly every message. If i use your code, I only receive a few messages -> over 80 % loss. The distance between the RaspberryPi and the Arduino is 1m. The frequency, spreading factor, bandwith, coding rate and crc settings are the same on both. Do you have an idea what could be the problem?

Greetings

mruijter commented 5 years ago

Are your messages coded as fixed blocksize? The example config assumes 32 byte fixed length messages. A mismatch could explain the problem.

Michael-List commented 5 years ago

Yep i set it to a fixed size. Tested different blocksizes also. Did you include another filter or configured something different like in the original repo?

mruijter commented 5 years ago

The main difference between the original code and this code is that changing speed and SF now actually works.

You can easily diff the two. The PI is the receiver?

Michael-List commented 5 years ago

Ok. I will make a diff and look at this details. Yes the pi is the receiver

mruijter commented 5 years ago

wfd = open_create_fifo(LORASEND_FIFO, O_RDWR | O_NONBLOCK);

The data is written to the pipe using non blocking io. So reading it when it arrives is required or the data will be discarded.

Maybe it’s helpful to turn on debugging in the config. It shows the data when it’s received in hex.

mruijter commented 5 years ago

I can reproduce the problem. I created a numbered packet stream and I am missing packets after correctly receiving a batch of them. Working on a fix..

Michael-List commented 5 years ago

Ok that are good news. I was about to make some tests tomorrow. But with this news I'm waiting for your fix.

Michael-List commented 5 years ago

I found the problem. If i delete the line writeReg(REG_OPMODE, OPMODE_LORA); // Set the register enabled for Lora. I receive every packet I send.

mruijter commented 5 years ago

Thanks Michael. I read the sx1276 manual twice. And I fail to see why this code was problematic. However the original code did not have it and I set the opmode to lora later on. So it was redundant at best. I’ve removed it.

Michael-List commented 5 years ago

Thanks for your help mruijter. This issue refers to commit a2f1da5b3c2dbcf3d159d39bf5fb4b3ad6ea96fc