nRF24 lib for Ruby

nrf24-ruby is a pure Ruby library for controlling the ubiquitous nRF24l01(+) radio module. Currently primary target is the Raspberry Pi, but it shouldn't be too hard to port to a different platform (supporting SPI).

No webserver, no message bus, no frills, yet a fully functional lib written in clear Ruby. (If you're in need of frills, bells, whistles and the like. This library gem works merrily together with all kinds of whistle implementing gems 😄)

This gem was based on the C++ RF24 library by tmrh20. I made the Ruby implementation mostly because wrapping C++ from Ruby sucks donkey balls.

Currently there's only one hardware driver included, which relies on the bcm2835 gem that wraps the bcm2835 C library. Therefore we need this C lib installed on our system.

Build the lib

wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.49.tar.gz
tar zxvf bcm2835-1.49.tar.gz
cd bcm2835-1.49
./configure
make
sudo make check

Make the shared library (.so file) and copy into the correct location

cd src
gcc -shared -o libbcm2835.so bcm2835.o
sudo cp libbcm2835.so /usr/local/lib

In case you don't feel like building the lib yourself, it's included in /binlib at your convenience.

Caveat: currently we're calling directly into the BCM2835's protected memory space, so we need to run as root.

Add this line to your application's Gemfile:

gem 'nrf24-ruby'

And then execute:

$ bundle

Or install it yourself as:

$ gem install nrf24-ruby

require 'nrf24-ruby'

The lib may be called using a block

NRF24.begin {

  set_channel 23
  
  print_regs

  open_reading_pipe 1, [65, 65, 65, 65, 65]
  
  start_listening

  loop do
    p read if data_available?
    sleep 0.01
  end

}

Or use the plain old instance based approach

nrf = NRF24.new(channel: 0x4c)

nrf.rf_setup :rate_250kbps, :max_power

address = 'AAAAA'.unpack('c*')
nrf.open_reading_pipe 1, address

nrf.start_listening

loop do
  if pipe = nrf.data_available?
    puts "data on pipe #{pipe}, fifo flags: #{nrf.fifo_flags}"
    data  = nrf.read
    p data
  end

  sleep 0.1 # Currently interrupt handling is not supported on Raspberry Pi, so we need to poll for new data
end