Magnetic Flap-Type Difunctional Sensor for Detecting Pneumatic Flow and Liquid Level Based on Triboelectric Nanogenerator

In recent years, the triboelectric nanogenerator (TENG) has attracted increasing attention because it not only converts various mechanical energy into electrical energy but also produces electrical signals as responses. On the basis of the TENG, a magnetic flap type difunctional sensor (MFTDS) has been developed to detect pneumatic flow and liquid level. Consisting of an outer magnetic flap, an inner magnetic float, and a conical cavity, its working mechanism and output characteristics were studied. The MFTDS detects pneumatic flows from 10 to 200 L/min with a flow resolution of 2 L/min. Compared with a commercial flow switch, the MFTDS results are in good agreement. Moreover, the MFTDS detects changes in liquid levels. The effects of liquid level height and flow rate on the performance of the MFTDS were measured and compared with a commercial liquid-level sensor. The results indicate that the output voltage of the MFTDS varies linearly with height but is independent of flow rate. The heights of liquid level from 30 to 130 mm were effectively detected. This work promotes the prospect for multifunctional triboelectric sensors.