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Make Peaches' Laser Harp [How-To]

Peaches is a great example of a musician that has used the digital revolution to her advantage, whether it be incorporating projections of collaborators, like Iggy Pop, into her live performances, or using instruments that make her musical processes more visible. She says herself, “my music is so minimal that you can see how it’s made if you play it on the lasers.” But even though it looks easy (and really fun to play), the process of making the actual laser harp is by no means effortless.

This week’s how-to, originally published by MAKE Magazine, is from Stephen Hobley, who said he was originally inspired to make the instrument after seeing sythpop pioneer Jean Michel Jarre perform in 1986. Twenty-five years later, Hobley has several prototypes, and has even custom built a laser harp for English pop songstress Little Boots.

The harp outlined in this how-to runs on a MIDI controller, which means it doesn’t make the sound itself, but instead connects to an audio synthesizer that’s driven by the controller. Each of the six laser beams strike a photocell when interrupted by a player’s hand, prompting an Arduino microcontroller to send a MIDI “Note On” message. Additionally, a rage sensor reads the positioning of the hand, which allows for the sound’s qualities to change. We’d say this project is pretty difficult, but for experts, Hobley says you can finish within a day. See the full list of supplies, tools, and parts here.

The first step is building all the main electrical components starting with the power supply, light detector circuit board, and MIDI output jack. Then you’ll construct the power supply on the mini circuit board and adjust the voltage levels that will feed into the components.

Next, you’ll wire the photocells, rig the MIDI output jack to the Arduino, and connect the lasers to the photocells. Then you’ll manipulate the output of the range sensors, which actually fire the pulses of IR light, so they don’t produce additional noise.

Next you will download the Arduino programming software and upload the laser harp program to your device. Connect the MIDI jack to your computer and test. Once everything is working, you’ll take one of the laser pointers apart and adjust the voltage on the power supply board to match. Then you will make the frame for each individual laser and embed each one.

After that, you’ll attach range sensors to the lasers in order to make sure that breaking the laser beam with your hand will switch it off. Then you build the harp’s frame and adjust the currents of the six lasers so they’re under the voltage limit of the regulator.

All that’s left to do before you start playing is make sure you’ve connected everything properly and upload a program to the Arduino that will let you play notes. Hobley recommends purchasing Abelton Live in order to trigger drum loops and other musical sequences.

Visit MAKE Magazine’s How-To for further instruction, more detailed photographs, and tips on where to buy materials. Photo of Peaches courtesy of Holger Talinski.

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