A sensor is a component or device that converts collected information into signals that can be processed by a device. Humans act based on information they get from sight, hearing, smell, and touch, and devices can control or process it based on information from sensors. The signals (physical quantities) collected and converted by sensors include temperature, light, color, air pressure, magnetic force, velocity, acceleration, etc., which take advantage of the material changes of semiconductors. In addition to this, there are also biosensors that utilize biological substances such as enzymes and microorganisms. There are more than 30,000 types of sensors. To fully understand sensors, it is difficult to cross almost all manufacturing categories, and it is as difficult as identifying a sky full of stars. Common types of sensors are: temperature sensors, humidity sensors, pressure sensors, displacement sensors, flow sensors, liquid level sensors, force sensors, acceleration sensors, torque sensors, etc.