arduino_firmata

Arduino Firmata protocol (http://firmata.org) implementation on Ruby.

• Firmata is a protocol to controll Arduino from software on PC.
• You can embed Arduino code into Ruby application.
• Support sharing an Arduino between multiple processes.
• http://shokai.github.io/arduino_firmata

Install

% gem install arduino_firmata

Requirements

• Ruby 1.8.7 or 1.9.2 or 1.9.3 or 2.0.0
• Arduino (http://arduino.cc)
  • testing with Arduino Diecimila, Duemillanove, UNO, Leonardo, Micro and Seeduino v2.
• Arduino Standard Firmata v2.2
  • Arduino IDE -> [File] -> [Examples] -> [Firmata] -> [StandardFirmata]

ArduinoFirmata Command

% arduino_firmata --help
% arduino_firmata --list
% arduino_firmata digital_write 13, true
% arduino_firmata analog_read 0
% arduino_firmata servo_write 9, 145

Synopsis

• https://github.com/shokai/arduino_firmata/tree/master/samples

Setup

Connect

require 'arduino_firmata'

arduino = ArduinoFirmata.connect  # use default arduino
arduino = ArduinoFirmata.connect '/dev/tty.usb-device-name'
arduino = ArduinoFirmata.connect '/dev/tty.usb-device-name', :bps => 57600
arduino = ArduinoFirmata.connect '/dev/tty.usb-device-name', :nonblock_io => true
arduino = ArduinoFirmata.connect '/dev/tty.usb-device-name', :eventmachine => true

Board Version

puts "firmata version #{arduino.version}"

Close

arduino.close

I/O

Digital Write

arduino.digital_write 13, true
arduino.digital_write 13, false

Digital Read

arduino.pin_mode 7, ArduinoFirmata::INPUT
puts arduino.digital_read 7  # => true/false

## regist event
arduino.on :digital_read do |pin, status|
  if pin == 7
    puts "digital pin #{pin} changed : #{status}"
  end
end

Analog Write (PWM)

0.upto(255) do |i|
  arduino.analog_write 11, i
  sleep 0.01
end

Analog Read

puts arduino.analog_read 0  # => 0 ~ 1023

## regist event
arduino.on :analog_read do |pin, value|
  if pin == 0
    puts "analog pin #{pin} changed : #{value}"
  end
end

Servo Motor

loop do
  angle = rand(180)
  arduino.servo_write 11, angle
  sleep 1
end

Sysex

• http://firmata.org/wiki/V2.1ProtocolDetails#Sysex_Message_Format
• https://github.com/shokai/arduino_firmata/tree/master/samples/sysex

Send

arduino.sysex 0x01, [13, 5, 2]  # command, data_array

Regist Receive Event

arduino.on :sysex do |command, data|
  puts "command : #{command}"
  puts "data    : #{data.inspect}"
end

Block Style

ArduinoFirmata.connect do
  puts "firmata version #{version}"

  30.times do
    an = analog_read 0
    analog_write 11, an
    sleep 0.01
  end
end

Test

Install SysexLedBlinkFirmata into Arduino

• https://github.com/shokai/arduino_firmata/blob/master/samples/sysex/StandardFirmataWithLedBlink/StandardFirmataWithLedBlink.ino

Run Test

% gem install bundler
% bundle install
% export ARDUINO=/dev/tty.usb-device-name
% rake test

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request