Electricity-Free Touchpad Opens Doors for Medical Devices

Researchers from Tampere University have developed the first soft touchpad capable of detecting the location, force, and contact area without using electricity. Traditionally, electronic sensors have been required for such functionality, but this new touchpad utilizes pneumatic tubes embedded within the device to sense objects without electrical power. The study was published in Advanced Intelligent Systems.

The device, which is made completely of soft silicone, has 32 touch-adaptive channels, each only a few hundred micrometers wide. It can detect multiple simultaneous touches and is precise enough to identify handwritten letters on its surface, as well as determine the force, area, and location of each touch.

Electronic sensors may stop functioning in extreme conditions, such as in a strong magnetic field. Since the touchpad is not electric, a strong magnetic field does not affect it, which makes it ideal for use in devices such as MRI machines.

Vilma Lampinen, Doctoral Researcher, Tampere University

The touchpad's sensor technology could enable pneumatic robots to perform procedures like biopsies during MRI scans for cancerous tumors, using MRI imaging data for precise guidance. This pneumatic device is also suited for environments with high radiation or where even a minor electrical spark could be hazardous.

Since silicone is a flexible material, these sensors can be integrated into applications unsuitable for traditional rigid electronics, such as soft robots, which are typically powered by pneumatics and made from materials resembling soft rubber.

In the future, integrating sensor data could map location, force, and contact area across the entire surface of such soft, non-electric devices. This advancement could enhance soft robotics and add a sense of touch to advanced prosthetic hands.

Soft robotic hands could be used to replace current prosthetic hands-on, e.g., production lines. Being soft, they are safer, lighter, and potentially cheaper to manufacture.  Touch sensors around the hand would also enable a more delicate grip.

Vilma Lampinen, Doctoral Researcher, Tampere University

Wearable technology made from soft materials holds potential as a movement aid in rehabilitation. Compared to comparable hard devices, its softness enhances user comfort.

Journal Reference:

‌Lampinen, V., et al. (2024) Soft Micropneumatic Touchpad. Advanced Intelligent Systems. doi.org/10.1002/aisy.202400381.