diary

Soundscape (Wave Alchemy)

A physical-visual language of emotionally expressive waveforms · ACM CHI 2013

Team
Dan Sawada, Anirudh Sharma, Sujoy Kumar Chowdhury, Christine Hsieh, Andrea Miller
Context
MIT Media Lab, 99 Fridays. Paper accepted at ACM CHI 2013.
Exhibition
MIT Museum, embodied HCI exhibition

Most of the energy we encounter in daily life – a voice, a gust, a vibration – arrives as a waveform and vanishes. We sense its emotional weight in the moment but have no physical artifact to return to. Photographs freeze a scene; audio recordings flatten it. Neither preserves the felt quality of the energy itself.

Wave Alchemy asks what happens when you give that energy a body. The system captures an acoustic or kinetic signal, decomposes it into frequency components, and drives an array of pin-actuated rods whose heights trace the waveform in three dimensions. Each rod is topped with a spherical element, and the ensemble forms a standing-wave sculpture that evolves in real time. The result is a tangible object you can walk around, a physical rendering of the original signal's spectral content.

The sculpture is built on the Radical Atoms framework developed at the MIT Media Lab – the idea that physical materials should be as malleable and dynamic as pixels on a screen. Each pin is individually addressable through a linear actuator stage, driven by a microcontroller interpreting incoming waveform data. Multiple overlapping sine waves create complex interference patterns: double-helix formations, travelling pulses, and resonance nodes that shift as the input changes.

Wave Alchemy sculpture showing pin-actuated rods in a standing wave pattern
Pin-actuated rod array with spherical tips forming a double-helix standing wave. Each rod is individually driven by the decomposed frequency spectrum of an input signal.

The interaction model is deliberately simple: approach the sculpture, and it responds to ambient sound or movement in the room. The emotional register of the input – sharp and percussive, slow and rolling – maps directly onto the physical form. A whisper produces gentle undulations; a clap triggers a sharp transient that propagates outward from the center. The sculpture becomes a kind of seismograph for the emotional texture of a space.

Demonstrated at the MIT Museum as part of an exhibition on embodied human-computer interaction, Wave Alchemy explores how computational materials can bridge the gap between ephemeral sensory experience and lasting physical form.

Sawada D., Sharma A., Chowdhury S.K., Hsieh C., Miller A. 2013. Wave Alchemy: Perception and Reminiscence of Expressive Moments through Waves. ACM CHI 2013. Paper