Project Overview

I built the Laser Harp as part of Digital Musical Instrument Design, a course led by Stephan Moore at Northwestern University. The instrument emerged from a desire to explore gesture as both input and output—a bridge between physical movement and digital sound.

Inspirations and References

This project builds on a lineage of laser-based musical instruments, especially the iconic MIDI laser harps popularized by Jean-Michel Jarre in the 1980s. My version was also shaped by open-source laser harp projects and forums like:

• Max/MSP serial communication tutorials from Cycling ‘72
• Laser Harp Frameless

Mechanical Design

The final instrument uses an Arduino, four laser diodes, and four ultrasonic distance sensors. Each laser is paired with a distance sensor, so when a hand enters the beam’s path and crosses into a specific distance range, it triggers a Max patch that plays sound.

My code can and compressed max patch can be found here

Sound Design

In Max/MSP, I built a digital synthesizer that responds to gestures. When a hand interrupts one of the beams and is within range of my sonic distance sensor, the synth is triggered. The distance between the hand and the sensor is then mapped to pitch, allowing expressive control over tone. . Each laser beam controls a slightly different version of the same synth. The synth responds to parameters like:

• Modulation frequency & ratio: These shape the harmonic content of the sound. Higher values introduce more complex or metallic textures.
• Brightness: A general term here, mapped to filter cutoff or harmonic intensity—brighter sounds have more high-frequency energy.
• Attack, Decay, Sustain, Release (ADSR): These define how a note behaves over time.
  • Attack is how quickly it starts,
  • Decay is how fast it settles,
  • Sustain is the level it holds at, and
  • Release is how it fades out.

Playing with these changes how percussive, sharp, smooth, or lingering the notes feel.