Silicone Devices: A Scalable DIY Approach for Fabricating Self-Contained Multi-Layered Soft Circuits using Microfluidics

Silicone Devices are self-contained and thus embed components for input, output, processing, and power. Our approach scales to arbitrary complex devices as it supports techniques to make multi-layered stretchable circuits and buried VIAs. Additionally, high-frequency signals are supported as our circuits consist of liquid metal and are therefore highly conductive and durable. To enable makers and interaction designers to prototype a wide variety of Silicone Devices, we also contribute a stretchable sensor toolkit, consisting of touch, proximity, sliding, pressure, and strain sensors. We demonstrate the versatility and novel opportunities of our technique by prototyping various samples and exploring their use cases. Strain tests report on the reliability of our circuits and preliminary user feedback reports on the user-experience of our workflow by non-engineers.


Scientific Publication:

Steven Nagels, Raf Ramakers, Kris Luyten, Wim Deferme. Silicone Devices: A Scalable DIY Approach for Fabricating Self-Contained Multi-Layered Soft Circuits using Microfluidics. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (CHI '18).
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Instructable Tutorial:

We wrote an instructable tutorial with more details on how to make Silicone Devices yourself: http://www.instructables.com/id/Silicone-Devices/

Overview:

This project demonstrates how to fabricate a durable highly stretchable device using only a laser cutter. The stretchable device is different from traditional stretchable or flexible sensors in that it seamlessly embeds I/O sensors, microcontrollers, battery power, and wireless communication modules. Our fabrication approach uses basic stencils and casting silicone and scales to arbitrary complex circuit layouts as it supports stretchable (buried) VIAs. The conductor embedded in the silicone is a liquid metal alloy and remains liquid after casting. In contrast to conductive inks, stretching therefore does not permanently alter the conductive properties of Silicone Devices and our prototypes only break when liquid escapes as a result of extreme forces that tear the silicone. In our stretch studies, we stretched samples up to 400% after which the circuit still self-healed upon release. The figures below give an overview of our fabrication techniques and resulting prototypes. For more information see our scientific paper or video.




A stretchable wristband embedding all sensors for input, output, processing, and power.


(Right) a stretchable Arduino Uno platform. (Left) a stretchable segment display.


(Right) a stretchable tattoo with embedded strain gauge to track bending of the arm. (Left) leveraging Silicone Devices for thermoforming rigid objects.