Musical festivals are fun and exciting. They are an opportunity for people to perform and show-off their art. The Boulevardia event held this June in Kansas City was one such event, where one of the interactive exhibits was a 12-foot guitar that could be played. [Chris Riebschlager] shares his experience making this instrument which was intended to welcome the visitors at the event.
The heart of this beautiful installation is a Bare Conductive board which is used to detect a touch on the strings. This information is sent over serial communication to a Raspberry Pi which then selects corresponding WAV files to be played. Additional arcade buttons enable the selection of playable chords from A through G, both major and minor and also give the option to put the guitar in either clean or dirty mode.
The simplicity of construction is amazing. The capacitive touch board is programmed using the Arduino IDE and the code is available as a Gist. The Raspberry Pi runs a Python script which makes the system behave like an actual guitar i.e. touching and holding the strings silences it while releasing the strings produces the relevant sound. The notes being played were exported guitar notes from Garage Band for better consistency.
The physical construction is composed of MDF and steel with the body and neck of the guitar milled on a CNC machine. Paint, finishing and custom decals give the finished project a rocking appearance. Check out the videos below for the fabrication process along with photos of the finished design.