Wireless Chat Using NRF24L01+ 2.4GHz RF Transceiver on Arduino & Raspberry Pi Ubuntu Linux

  • 17/8/2020
  • 2-minute read

After a bit of success implementing an Arduino 2.4GHz Transceiver , I was encouraged to explore a more familiar environment, something with Python and Linux in the mix.

After a short period of research I landed on the circuitpython-nrf24l01 pypi project page, and quickly began digging through their examples .

It wasn’t long after I had a working prototype that mirrored my Arduino code quite closely:

Components

import sys
import select

from circuitpython_nrf24l01 import RF24
import board
import digitalio as dio

# addresses needs to be in a buffer protocol object (bytearray)
address = b'Nessy'

# change these (digital output) pins accordingly
ce = dio.DigitalInOut(board.D4)
csn = dio.DigitalInOut(board.D5)

# using board.SPI() automatically selects the MCU's
# available SPI pins, board.SCK, board.MOSI, board.MISO
spi = board.SPI()  # init spi bus object

# initialize the nRF24L01 on the spi bus object
nrf = RF24(spi, csn, ce, ask_no_ack=False, data_rate=250)
nrf.dynamic_payloads = False # this is the default in the TMRh20 arduino library
nrf.payload_length = 32

# get username
username = input('Enter Username: ')

# set address of RX node into a TX pipe
nrf.open_tx_pipe(address)

# set address of TX node into a RX pipe
nrf.open_rx_pipe(1, address)

nrf.listen = True

print('Welcome %s' % username)
while True:

    # handle write
    if select.select([sys.stdin,],[],[],0.0)[0]:
        nrf.listen = False
        for line in sys.stdin:
            msg = b'[%b] %b' % (username.encode(), line.rstrip().encode())
            nrf.send(msg)
            break

    # handle recieve
    if not nrf.listen:
        nrf.listen = True

    if nrf.any():
        # retreive the received packet's payload
        buffer = nrf.recv()
        data = buffer.decode().replace('\x00', '')
        print(data)
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