2, Pusan National University, Busan, , Korea (the Republic of)
Tilt sensor is a device that detects angular variation and make electrical signal. It gives us information about the horizontal and vertical state. It is related with stability so tilt sensor is very important part of structure. There are some special applications using tilt sensors such as airplanes, smart phones, game machines, automobile security systems, bridges and drones.
To sense angular changes, sensor needs critical characteristics. First, sensor have to work not only constantly for a long time but also stably. Most of tilt sensor include liquid because it flows downward due to gravity, this is the simplest mechanism. The solution used sensor should not be interacting with physically and chemically to maintain performance. Second, tilt sensor has return capability. When the angle is no longer changed and reached flat condition, sensor have to point horizontal value exactly.
Because of some essential feature, there is some limitation to make existing sensors. We have to consider about the internal material and also supply external power continuously. In this paper, we deal with a new triboelectric sensor (TS) as a self-powered sensor. The shape of TS is hexahedron with PTFE balls inside. TS consist of PTFT balls, acrylic box, and eight aluminum electrodes. Because of the use of solids as internal material, there is no need to consider environmental and chemical degradation. When PTFE balls rolls inside the acrylic box, electric potential difference will be made. Because triboelectric follows triboelectric series and caused by electrostatic induction and contact-electrification. When one PTFE ball is moved by gravity, the output voltage and current are 2 V and 20 nA, respectively. So TS does not require external power. It can act self-powered active system. The inclination and angle can be estimated by integrating the change of the voltage of 8 electrodes. A multi-channel system was designed and measured to observe the voltage change of 8 electrodes at one time. TS has simple structure, low-cost, economical, eco-friendly and self-powered system. This study will expand the application of triboelectric sensor.