Patent attributes
A liquid surface level sensor includes a housing, a float located on a liquid surface, a magnet that rotates in accordance with up-and-down movement of the float, an arm joined with the float and the magnet, and a circuit unit. The circuit unit includes a sensing element that detects rotation of the magnet, and a wireless communication circuit that outputs a liquid surface level detected by the sensing element to a device installed in a vehicle. The circuit unit includes generating element that generate electric power from a change in magnetic flux caused by the rotation of the magnet, and a generation circuit that supplies electric power generated by the generating element to the sensing element and the wireless communication circuit as drive electric power. The circuit unit is included inside the housing in a state isolated from the outside.
