Yokohama National University develop a liquid-based digital readable tilt sensor

A research group consisting of Associate Professor Hiroki Ota and his colleagues of the Graduate School of Engineering, Yokohama National University, have developed a tilt sensor using a conductive liquid material that captures a digital binary signal. This device can acquire tilt information using binary signals such as the on/off state of direct current, and the group has succeeded in the simultaneous measurement of the tilt angle and and direction in two dimensions. This was difficult with the conventional digital lead tilt sensor using a conductive liquid.

Among the physical sensors being studied, tilt sensors play important roles such as the attitude control of robots and have applications in wearable devices. Conventional tilt sensors tend to have a complicated measurement system owing to the use of AC for measurements. To address this problem, the research group has made it possible to directly measure the tilt angle with DC current by using a conductive liquid in which carbon fine particles are dispersed. This device is capable of measuring the tilt angle by using binary signals such as by turning a current on/off, and it realizes the simultaneous measurement of the tilt angle (depth) in one direction and the tilt direction, which was difficult with the conventional digital lead-type tilt sensor.

During manufacturing, wiring is provided on the substrate using microfabrication technology, and a shell produced by 3D printing technique is laid on the upper part. A conductive liquid is encapsulated inside the shell and detecting the movement of the liquid in response to tilt can be used to measure the angle and direction of the tilt. Direct current is used to detect the movement of the liquid, and the tilt information can be obtained by detecting the electrode on which the current is turned on. Prof. Ota commented, "In the future, we aim to combine these sensors with numerous physical sensors such as pressure, tension, light, and temperature, and to use them as compact multi-physical sensors. A single compact device that can collect different physical information will have applications in robotics and small wearable devices."

This work was supported by PRESTO (grant no. JPMJPR18J2) and CREST (JPMJCR1905) from the Japanese Science and Technology Agency. H.O. acknowledges support from a Grant-in-Aid for Scientific Research (A) provided by the Japanese Society for the Promotion of Science.