A research team at Kyoto Institute of Technology has newly developed a fabric-type touch/pressure sensor that can operate in a non-powered state.This sensor is a textile-type pressure sensor that can be knitted in one operation using only conductive and insulating yarns, and because it is entirely made of yarn, it has excellent breathability, is lightweight, flexible, and feels good on the skin. Good and washable.In addition, since touch sensing and pressure sensing are performed using electromagnetic waves that are constantly dissipated in the environment, unpowered operation is possible.
The touch/pressure sensor weighs about 20 g for a size of 20 mm x 0.50 mm, and the price varies depending on the yarn used, but the material cost per 20 mm x 20 mm size yarn used in this research is about 1 yen. It was inexpensive. It has a spacer fabric structure like a five-layer knitted fabric, and each of the front and back sides consists of a two-layer knit structure with an insulating yarn layer on the outside and a conductive yarn layer on the inside.In between is a spacer layer that forms a space while connecting the front and back surfaces.
When the voltage generated across the capacitor is measured when the surface of the knitted sensor is touched and pressed with a human finger, a slight voltage is output when the finger is not in contact, and the output voltage is output when the finger touches. increased significantly, and an increase in output voltage was observed with further pushing.When it was further pushed in excessively, the upper and lower conductive thread layers were short-circuited, and the output voltage became 0.0V.In other words, the developed sensor can detect human touches and pressures based on the magnitude of the output voltage, and can also detect excessive pressing, and does not require power supply from an external power supply.
Such a sensor is suitable for application development as a hands-on/off detection sensor for the steering wheel of electric vehicles and self-driving vehicles, for example. I expected it to work.This result is expected to contribute to the power saving and simplification of automobile steering wheel sensors and the improvement of driver comfort.
Paper information:[Smart Materials and Structures] Active signal-generating spacer-fabric-type continuous touch/pressure sensor
