We present SqueezaPulse, a technique for embedding interactivity into fabricated objects using soft, passive, low-cost bellow-like structures.
SqueezaPulse is comprised of three core parts: (i) a soft and squeezable cavity to generate airflow; (ii) a tube designed with specific inner-wall corrugations to shape the airflow into unique acoustic signatures, effectively acting as a physical filter; and (iii) a microphone connected to a computer that classifies these signatures for interactive inputs. When a soft cavity is squeezed, air pulses travel along a flexible pipe and into a uniquely designed corrugated tube that shapes the airflow into predictable sound signatures. The microphone captures and identifies these air pulses enabling interactivity.
We used the theory of corrugated acoustics to inform our design and conducted an informal examination of the effect of different 3D-printed corrugations on air signatures. As a result, corrugated tube length, inner diameter, corrugation distribution, space between corrugations, corrugation shape all affect the generation of distinct air flows.
To demonstrate and evaluate the potential of SqueezaPulse, we present four prototype applications (a gamepad controller, an interactive bunny, a smart case, and a force sensor) to show our approach is accurate across users and robust to external noise.