Photoelectric inclination sensor

A new photoelectric inclination sensor consisting of a light emitting diode (LED) spirit level mounted on a photodiode array is introduced. Light from the LED projects a bubble in the level and throws a shadow onto the surface of the array composed of four equivalent square‐shaped diodes, isolated from each other by a cross on a wafer. When the transducer is kept horizontal, the area of the shadow in each diode is exactly equivalent. By taking the difference output positioned obliquely in the array, the water level in the two‐dimensional plane is detected. This transducer detects the two‐dimensional water level accurately, can be compact, and the response is fast.