Vol. 15: Laser Harp

Play strings of light, using laser pointers, rangefinders, photocells, and Arduino.

+ Downloads & Extras:

Code zip file

Schematics zip file

Analog multiplexor:

AIN Kit (32 analog inputs) from http://www.avishowtech.com/mbhp/mbhp_ainR4.html

This uses 4 standard 4051 analog multiplex chips – documentation is available on the internet on how to use the control lines to connect to each of the 32 inputs.

Note: With some clever programming you can use just the analog multuplexor to drive the laser harp – connect the outputs of the photocell array directly into the inputs of this board, then you can detect if a beam is broken in software inside the Arduino.

Digital Multiplexor:

DIN Kit (32 Inputs) from http://www.avishowtech.com/mbhp/mbhp_dinR5.html

This kit uses the 74HC165 chips these take the parallel input lines and create a serial stream, you can chain these modules together and have as many inputs as you need. Documentation is available online - the Arduino playground is a good place to start.


More than anything this project has been a testament to the collaborative power of the Internet. I could not have done any of this without the help of many people – who were good enough to answer all the questions I posted on a variety of forums. I'd like to take this opportunity to pass on my gratitude - please keep up the good work! If you want to tackle a full sized scanning laser harp – then more information can be found on my website www.stephenhobley.com.

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