Optical sensors are essential in systems that require light detection for measurement, control, or triggering actions. They are available in different types, such as photodiodes, phototransistors, and light-dependent resistors (LDRs), each suited for specific use cases. Mainly, it combines the infrared light-emitting diode (LED) and a phototransistor. an optocoupler of a closed pair configuration is enclosed in the dark resin and is used to transfer signals using light. The semiconductor development from 1940 to the 1950s led to compact, less costly, and efficient light-sensing devices like optical. An optical sensor is a device that detects light and converts it into an electrical signal. Holtek has released a 32-bit Arm Cortex-M0+ Optical Module DDM MCUs, the HT32F52234 and HT32F52244.
[pdf] This research presents a low-cost sensor for measuring liquid levels using plastic optical fibers (POF). In this paper, a novel liquid level sensing system is proposed to enhance the capacity of the sensing system, as well as reduce the cost and increase the sensing accuracy. The sensor reduces the scattering-based optical losses in the fiber, which increase linearly with the liquid height.
[pdf] 
