Give a $6 microcontroller a handful of copper pads and it can turn almost any object into a playable instrument. That is exactly why maker and engineer Monique Evette's latest build matters: it proves that expressive, professional-grade music gear no longer needs a factory behind it, just a Raspberry Pi Pico and some clever sensing.
A guitar shaped like a frozen splash
The instrument, nicknamed the Koi-Tar, walked the runway at New York Fashion Week as part of Evette's Whimsical Machines series. Its translucent resin body is sculpted to look like a koi pond caught mid-splash, complete with lily pads that double as the playing surface. Musicians Benn Jordan and Venus Theory put early versions through their paces and fed notes back into the design, so this is a working controller, not just a display piece.
How the electronics work
At its heart sits a Raspberry Pi Pico mounted on a SPOKE-mini capacitive-touch board. Each lily pad is a copper pad on a custom PCB; when your finger touches it, the change in capacitance is read by the Pico and converted into a MIDI note. Because the Koi-Tar speaks MIDI rather than generating its own audio, it can drive any synth, software instrument, or DAW you plug it into. The resin shell was modelled in Blender using water-physics simulations before being printed, which is what gives that splash its uncanny realism. Capacitive sensing is a favourite trick among makers precisely because it needs almost no extra hardware: the Pico already has the GPIO and processing headroom to watch dozens of pads at once and still stream MIDI without noticeable lag.
Build a touch instrument yourself
You can recreate the core idea on a student budget. You will need a Raspberry Pi Pico, a capacitive-touch breakout or a few copper pads wired to touch-capable GPIO, and a USB cable. Flash CircuitPython, add the MIDI library, and map each pad to a note. From there the enclosure is yours to design, whether that is a laser-cut panel, a cardboard prototype, or a full resin sculpture. It is an ideal capstone or thesis starting point: small parts count, big room for creativity. If you want a gentler on-ramp, start with four pads that trigger a drum kit, then scale up to a full chromatic layout once the sensing feels reliable.
Originally published on blog.circuit.rocks.
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