Mõistatus Vooluringid

My friend Alex Maiolo commissioned me to build a light to CV interface for his performance at the Tallinn Music Week in Estonia, 2021. The project is Themes For Great Cities (youtube link). The idea is to take elements of the city, and convert to sound. The device I built transforms light into control voltages for Alex's modular synthesizer. In Alex's words:

"It involves harvesting elements from the city to influence the music we compose. The city is the fifth band member, effectively. Audio recordings, sure, but what if we could gather light too? What if the sparkle of the harbor’s waters, the sky flickering through the trees could be converted to voltage, and that voltage could influence pitch, filtering, sequencer advances, and other things?"

In the performance: Alex Maiolo, Jonas Bjerre of the Danish band Mew, Erki Pärnoja, an Estonian solo artist who has composed for Arvo Pärt, and Estonian multi-instrumentalist Jonas Kaarnamets.

Mõistatus Vooluringid kind of translates to "Mystery Circuits" in Estonian. The color scheme is that of the Estonian flag.

The circuit is pretty simple.. It involves using a photo resistor as a voltage divider, and that sends the voltage through an op-amp voltage follower. The output's ground reference is adjustable with the knob on the top, and that allows CV to go between +5-0V, +/-2.5V, and -5 to 0v. There is a white LED that stays on inside. This slightly illuminates the "eye" on the face of the sensor, but its purpose is to keep the photo resistor from going completely open in 100% darkness, which causes the output to go all the way up. The Eye is a small acrylic hemisphere I bought at Canal Plastics when I lived in NY. It's all powered from a 9V battery.

I like how someone on social media said it looks like a vape device. It totally does!