Laser-light Music Harp

Laser-light Music Harp

What is a laser-light music harp? Can it play sound? Where are the strings? Can't it burn my eyes out? Well given a talented artist and some practice it can play sounds, or better, music. It does this by sensing the placement of your fingers as you "pluck" non physical strings made of red and green laser light. This is great in that it provides a very visual and aural experience for both the musician as well as the audience. It outputs a velocity sensitive MIDI stream that is fed into a synthesizer. It also has a built in practice mode which plays sound through an internal speaker. This way a synth does not have to be lugged around just to use the harp. I also designed in a 2 line LCD so a musician can choose from various options like velocity

sensitivity, MIDI channel, speaker volume and other programmable settings. A Microchip PIC 17C766 microcontroller runs the whole thing. This chip was choosen for its very robust on-board features. Few external electronics were required in the design. The 17C766 is a great chip...

I initially designed this for a friend of mine David Arkenstone. He is a two time Grammy nominated musician and he intends to use it in one of his upcoming concerts (when I finally complete it).

And no, it can't burn your eyes out.

This is the harp. It stands about 3 1/2 feet tall
and has 15 light-strings that can be "plucked"

This top section shows the 15 sensors used to detect the light beams. Each of the sensors are scanned many times a second and when a signal changes state this indicates that a beam has been broken. The rate of change indicates the velocity of pluck

This is the cowling that fits over the sensor array. The trick was to form a hunk of wood into this shape. I used the above image and traced the edges in PhotoShop then printed out a template to cut with

This shows the innards and the green laser module at the bottom right (in black). Its beam is passed through a network of variable percentage beam splitters in order to evenly break the one green beam into 10 lesser intense beams. These are then reflected via a complex array of mirrors where they each finally exit the front face of the harp toward the sensors. The 5 red beams are each a separate small laser diode module pointed directly towards the sensors. It was one heck of a challenge to properly align all these mirrors...

This shows the hardware. At the core is a Microchip PIC 17C766 microcontroller clocked at 33mhz. The LCD display is a 2 line version with on board EEPROM memory used to save harp settings. Wiring harnesses plug into this board from the sensors, lasers, MIDI, and power plugs