BrickBot: A BrickPi library for Ruby

ruby wrappers for the BrickPi Lego Mindstorms C library

What you need:

You need to have a few things to use this:

• The wonderful BrickPi from Dexter Industries
• A Raspberry Pi (if you didn't get one with the BrickPi)
• Lego Mindstorms NXT 2.0 motors and/or sensors

Installation

Note: This gem will currently only install on a Raspberry Pi set up with BrickPi software. It relies on the WiringPi.h C program to function and compile.

You'll first need Ruby installed on your Raspberry Pi. If you need help, this Stack Overflow answer may be of service: http://raspberrypi.stackexchange.com/questions/1010/can-i-install-the-ruby-version-manager

Add this line to your application's Gemfile:

gem 'brick-pi'

And then execute:

$ bundle

Or install it yourself as:

$ gem install brick-pi

Usage

Motors

Currently, you only get a set of primitives to run motors. Expect a more robust library supporting various configurations (e.g. 2-tracked vehicle) later on.

The Bot object starts and stops the robot. It contains 4 Motor objects, mapped to port A-D on your BrickPi.

Here's a quick & dirty script to spin a motor:

require 'brick_pi'

# Create a bot with a motor on port A
bot = BrickPi.create do |bot|
  bot.motor :port_A
end

# Get this party started
bot.run do

  # Set the speed for a motor, on a scale of 0 - 100
  bot.motor_A.spin 50

  # Run the motor for 1 second
  sleep 1

  # Stop a single motor
  bot.motor_A.stop

end

Once your bot is started, you can change the speed or direction of the motors at any time with the Motor#spin method.

Here's a really yucky script I hacked together to let you drive a 2-tracked vehicle with an iCade 8-Bitty (which is basically a bluetooth keyboard that looks like an NES controller).

It requires the Highline gem, so on the BrickPi you'll need to run gem install highline.

require "highline/system_extensions"
include HighLine::SystemExtensions
HighLine::SystemExtensions.raw_no_echo_mode

# Create a bot with two motors
bot = BrickPi.create do |bot|
  bot.motor :port_A
  bot.motor :port_B
end

bot.run do

  speed = 20
  loop do
    char = HighLine::SystemExtensions.get_character
    case char.chr
    when 'w'
      bot.motor_A.spin speed
      bot.motor_B.spin speed
    when 'd'
      bot.motor_A.spin speed
      bot.motor_B.spin 0 - speed
    when 'a'
      bot.motor_A.spin 0 - speed
      bot.motor_B.spin speed
    when 'x'
      bot.motor_A.spin 0 - speed
      bot.motor_B.spin 0 - speed
    when 'o'
      if speed >=0 && speed <= 80
        speed += 20
      end
    when 'l'
      if speed > 20 && speed <= 100
        speed -= 20
      end
    when 'e', 'c', 'z', 'q'
      bot.motor_A.stop
      bot.motor_B.stop
    end
    sleep(5 / 1000)
  end
end

Sensors

You can read values from sensors by doing something like this:

bot = BrickPi.create do |bot|
  bot.touch_sensor :port_1
end
bot.run do
  bot.sensor_1.read
end

See the scripts in the examples directory for more details.

Contributing

1. Fork it ( https://github.com/tehviking/brick_pi/fork )
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 a new Pull Request

Issues

I use HuBoard to manage GitHub issues. It's pretty awesome, check it out here:

https://huboard.com/tehviking/brick_pi_ruby/