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Carl Becker
Capacitive music & EMC

Capacitive music & EMC

·373 words·2 mins
EMC Lab Automation VCV Rack
Table of Contents

Hi!

At the moment, I do the course of electromagnetic compatibility (in short EMC) in my masters degree. When designing an electronic device, for example a robot, one has a lot of different parts: A computing part, telemetry, batteries, motor controllers and the motors themselves. They should all work at the same time, from the same battery! So they need to live in harmony with each other – in other words being electromagnetic compatible. Optimally, each part should not generate bad signals, transmit them to other parts and if it does, the other parts need to be immune to these signals. Preventing the generation, coupling of signals and making device immune to external signals is a complex task (the art of EMC).

Electronic signals can couple between devices in multiple different ways, one being capacitive. There is a lot of theory, so every now and then, I need to get physical and play around with the concepts to make sure the university isn’t just telling fancy made-up stories!

Making music with the amount of capacitive coupling
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Measurement setup
Figure 1: Measurement setup
  1. With my analog modular synth, I generate a ca. 10kHz square wave signal, ±5V.
  2. The signal is on a long wire on top of a grounded metal aluminium sheet
  3. With another long wire near to the signal wire, I capacitively pick up signals
  4. The oscilloscope shows the signals! (Unfortunately, the video only shows the picked up signals, not the original one)
  5. The oscilloscope measures peak-to-peak voltage automatically
  6. With a vibe-coded Python script, I retrieve the peak-to-peak voltage from my oscilloscope and emulate a midi device in real time
  7. The VCV Rack modular synthesizer makes some sounds from the midi signals!

As you see, I control the tone pitch using the amount of capacitance between the two cables, similar to a theremin.

Making music!
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Analog modular synthesizer rack, explained
Figure 2: Analog modular synthesizer rack, explained

Btw., this synthesizer program is called “VCV Rack”. It’s very cool since you can just put modules together as you like. It’s a little difficult to get started, but regarding making music, you have the most freedom, especially regarding sound design. And it’s free!

I am interested in your thoughts! - Reply with a simple Email

Have a nice day,

Carl