After being introduced to microcontrollers and Sharp IR range finder sensors from my other projects, I decided to build a laser harp after being inspired by a video from the Internet. This was my very first attempt to use an Arduino. I opted to build a custom shield since I couldn’t find anything remotely close to what I needed on the market.
The laser harp is really a set of 5 Sharp IR range finder sensors pointed up, each along side a laser pointer. The laser provides a visual reference for the IR beam since it’s invisible. When my hand breaks the plane of the IR beam (and the laser pointer beam), it’s read by the Arduino which then sends a MIDI signal to my electronic keyboard to make a sound. The frame is made of High Density PolyEthylene (HDPE) – easy to cut and work with, and inexpensive. I used some L brackets to mount smaller squares for individual aiming of each laser.
I had to tuck a lot of wiring into the back. The whole thing has only 2 external wires – a MIDI cable and a 9V power cord. I use alligator clips and hook clips to connect the laser pointers to the main circuit board’s 3V power supply so I don’t have to rely on batteries and can turn them all off with a single switch. The MIDI cable is connected to the serial connection of the microcontroller so I can send binary data to a keyboard which actually makes the music. I found a great Midi library on the Arduio site so the interface to MIDI was really easy.
I added a some dip switches so I could change the mode of the laser harp. The modes were:
- DIP 1 lets me play on the C Major scale
- DIP 2 plays octaves of different notes
- DIP 3 will play Axel F. A few notes are played per sensor – if you run your hand from left to right across all 5, it plays the full rif.
- DIP 4 plays “The Final Countdown” by Europe. Same idea as Axel F.
I later bought a smoke machine with thoughts of filling my garage with smoke and firing this baby up, but I never got around to it. :)