( ( ( AirHarp ) ) )
An open source ultrasonic digital autoharp!
As seen on SparkFun Electronics and Ask an Engineer with Limor "Ladyada" Fried!
"O mio babbino caro" on AirHarp
How to play the AirHarp (tutorial)
What is an AirHarp?The AirHarp is a type of digital autoharp that allows musicians of diverse skill levels to play music of advanced harmonic complexity simply by pressing four pushbuttons and "strumming" invisible harp strings in the air. Developed by musician-turned-engineer Peter DeSimone, the AirHarp is pocket-portable and suitable both as an introductory instrument and an accompaniment tool for singers and songwriters. It allows direct access to fourteen chords within a given key (including the seven diatonic chords), and can automatically transpose to any key with the push of a button. This allows the AirHarp to easily play most songs, from baroque arias to modern rock songs. As a "plug and play" USB MIDI controller, your AirHarp can sound like any instrument in existence. With thousands of software synthesis ("softsynth") sound banks available today, you will always be discovering new sounds to make with your AirHarp.
To illustrate exactly what I mean by this, I created the following song in about an hour using nothing but a standard AirHarp and an awesome music production program called Apple Logic:
All the sounds you hear were played on the AirHarp with the exception of the drum tracks, which are canned samples. I could have used the AirHarp for the drums as well, but I'm no percussionist and I have trouble conceptualizing music in purely rhythmic terms. Thus I will leave the exploration of the AirHarp's percussion capabilities to someone else.
How does it work?The AirHarp emits a beam of ultrasound that's undetectable to the human ear. It bounces this beam off your free hand to determine the distance between your hand and the device. This is a form of ultrasonic sonar ranging. A microcontroller continuously monitors the output of this sensor, along with the status of each pushbutton. Calculations are performed to decipher the coded chord input and compute the desired note pitches based on readings from the ultrasound. A list of active notes is maintained and used to determine which notes to turn off and when. Information on which notes to activate and deactivate is coded into a serial data format called MIDI and transmitted out of the microcontroller into either a synthesizer module or to an outboard computer through a USB cable. The synthesizer module or computer then converts these "note on/off" commands into audible sound.
Where do I get one?!Instruments and kits are available now from the Lyratron store! All harps are currently hand assembled by Peter DeSimone in Socorro, New Mexico, USA, or Erik Jacobson in Ventura, California, USA. We are actively seeking business partners who can help us bring the AirHarp to a larger audience.
Can I build my own?Yes you can! In the spirit of the open source movement that made the AirHarp possible, we have published all the required schematics and source code under a Creative Commons Attribution-Noncommercial-ShareAlike license. Check out the following links:
How to build an AirHarp (Instructables)
Lyratron Store (sells AirHarp parts & kits)
3-D Printable Cases
AirHarp Photo Gallery
AirHarp Firmware for Arduino
AirHarp Chord Guide
AirHarp Songbook (work in progress)
AirHarp Shield Eagle / Gerber files
AirHarp Nano Eagle / Gerber files