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This gem provides an interface to access novation's launchpad programmatically. LEDs can be lighted and button presses can be responded to. Internally, launchpad's MIDI input/output is used to accomplish this.

The interfaces should be rather stable now (sorry, I changed quite a bit since the last release), so experiment with them and comment on their usability. This still is work in progress. If you need anything or think the interfaces could be improved in any way, please contact me.

Sometimes, the launchpad won't react to anything or react to/light up the wrong LEDs. Don't despair, just dis- and reconnect the thing. It seems that some (unexpected) MIDI signals make it hickup.



The gem is hosted on Gemcutter, so in order to use it, you're gonna install the gemcutter gem (for details, see their site):

gem install gemcutter
gem tumble

After that, it's a simple gem install:

gem install launchpad


There are two main entry points:

  • require 'launchpad/device', providing Launchpad::Device, which handles all the basic input/output stuff

  • require 'launchpad/interaction' or just 'launchpad', additionally providing Launchpad::Interaction, which lets you respond to actions (button presses/releases)

This is a simple example (only requiring the device for output) that switches on all LEDs (for testing), resets the launchpad again and then lights the grid button at position 4/4 (from top left).

require 'rubygems'
require 'launchpad/device'

device =
sleep 1
sleep 1
device.change :grid, :x => 4, :y => 4, :red => :high, :green => :low

This is an interaction example lighting all grid buttons in red when pressed and keeping them lit.

require 'rubygems'
require 'launchpad'

interaction =
interaction.response_to(:grid, :down) do |interaction, action|
  interaction.device.change(:grid, action.merge(:red => :high))


For more details, see the examples. examples/color_picker.rb is the most complex example with interaction.

Near future plans

  • close devices properly

  • interaction responses for presses on single grid buttons/button areas

  • double buffering

  • bitmap rendering


Copyright © 2009 Thomas Jachmann. See LICENSE for details.

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