Eirik Brandal's "Shell-Tethered Vespa" Is Part Circuit Sculpture, Part Synthesizer, All Awesome

Powered by an Electrosmith Daisy Seed, this gorgeous wall-hanging art piece generates a new tune every time you pass.

Gareth Halfacree
4 months agoMusic / Art

Artist Eirik Brandal has unveiled his latest electronic sculpture, blending sound and light under the control of an Electrosmith Daisy Seed microcontroller board: the "shell-tethered vesper," designed for wall hanging and offering a four-voice synthesizer with built-in light show.

"Shell-tethered vesper is a wall-hanging generative sound and light sculpture built on the digital signal processing capabilities of the Daisy Seed in tandem with analog oscillators, voltage controlled amplifiers and filters," Brandal explains of his latest creation.

The "shell-tethered vesper" is a true blend of science and art, and the latest sculpture from Eirik Brandl. (📹: Eirik Brandal)

"At its center," Brandal continues, "RGB light pipes visualize changes in various parameters within the code, while white LEDs on the second level are triggered by sequencers on which the algorithmic composition is based on. Beneath sits a 3D printed speaker enclosure that houses two ND65 speakers with matching passive radiators, powered by a TPA3110D2 class D 15W/[channel] stereo amplifier."

The heart of the build is the Daisy Seed, a breadboard-friendly microcontroller development board designed by Electrosmith specifically for audio work. The compact board includes an audio codec offering up to 96kHz/24-bit output, 64MB of SDRAM, and a single Arm Cortex-M7 microcontroller core running at 480MHz. There's an SD Card interface for additional storage, pulse-width modulation (PWM) outputs, and two 12-bit digital to analog converters (DACs).

In the shell-tethered vesper, the microcontroller is used to drive a four-voice hybrid analog/digital synthesizer engine, the analog side being made up of a pair of oscillators, a dual voltage-controlled amplifier, and a -24dB per octave low-pass filter. This is used to generate unique audio each time the sculpture is triggered by its built-in passive infrared (PIR) motion sensor, providing new audio every time. A central display made up of RGB LEDs firing into light-pipes visualizes exactly what's going on as the audio is generated.

The sculpture combines analog and digital circuitry to make a motion-triggered generative four-voice synth. (📹: Eirik Brandal)

This is far from Brandal's first electronic sculpture. Back in May last year he unveiled Várhafsóll, a musical circuit-sculpture inspired by traditional Scandinavian cow-herding songs and powered by the Espressif ESP32-S2-Saola. In February 2022 he was showing off the cwymriad, an earlier ESP32-powered design where the microcontroller was put in charge of a dual ring-modulation circuit to control the carrier and modulation signals.

More information on the project is available on Brandal's website, along with a demonstration video and a making-of video.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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