NRF24L01 multiple transmitters, one receiver

Question

Helo!

I want to build a system, where multiple transmitters (in my case - Arduino Pro Mini) send data to one RPi 2 over NRF24L01. I'm using C++ library for NRF24 from here. On basis of examples/extra/rpi-hub.cpp I managed to receive from two arduinos. However, when I print pipe number inside loop, it is always set to 0. I need to know from which arduino/pipe I received data and that's the point I've stuck.

My RPi code:

const uint64_t pipes[6] = { 0xF0F0F0F0D2LL, 0xF0F0F0F0E1LL, 
                            0xF0F0F0F0E2LL, 0xF0F0F0F0E3LL, 
                            0xF0F0F0F0F1, 0xF0F0F0F0F2 };
radio.begin();
// optionally, increase the delay between retries & # of retries
radio.setRetries(15,15);
// Dump the configuration of the rf unit for debugging
radio.setChannel(70);
// radio.openWritingPipe(pipes[0]);
radio.openReadingPipe(1,pipes[1]);
radio.openReadingPipe(2,pipes[2]);
radio.startListening();
radio.printDetails();

while (1)
{
    uint8_t pipe = 2;

    while ( radio.available(&pipe) ) 
    {
        radio.read( &data, sizeof(myData) );
        printf("Recv: pipe=%i\n", pipe);        
        cout << " Temp: " << data.temp << " humidity: " << data.humid << endl;
        delay(1000); //Delay after payload responded to, minimize RPi CPU time

        pipe++;

        // reset pipe to 0
        if ( pipe > 3 ) 
            pipe = 2;

    }       
}

I assume that it is not a problem with pipe addresses (beacuse data is coming to RPi), but I have no idea what other thing can be wrong. As I mentioned before, the only thing I found to be incorrect is pipe number set to 0, no matter what I assign in the beginning of the loop.

Answer 1

Use different variable for checking pipe number: Test whether there are bytes available to be read in the FIFO buffers.

Parameters
[out]   pipe_num    Which pipe has the payload available

uint8_t pipeNum;
if(radio.available(&pipeNum)){
  radio.read(&data,sizeof(data));
  Serial.print("Got data on pipe");
  Serial.println(pipeNum);
}

Returns
True if there is a payload available, false if none is
Definition at line 1055 of file RF24.cpp.

https://tmrh20.github.io/RF24/classRF24.html#ace7dd139fabc16b77cb8325faa07620f