ABSTRACT
The impedance of the sensor, which also comprises capacitive and inductive sensors, may change. This chapter discusses examples of the different types of sensors. The examples only show a selection of those available on the market, and searching the Internet for the physical quantity one wants to measure jointly with the keyword "sensor" will give an idea of what is available. In case the input voltage of the sensor exceeds the input range of what the microcontroller can handle, people have to reduce the voltage by a voltage divider, which consists of two fixed-value resistors. The analog signals from the sensors can be too high or too low. They can be too noisy or otherwise inadequate to directly feed to an analog-to-digital converter (ADC) or a microcontroller. Often, sensors produce small voltages that vary around zero, but the ADC requires an input range of 0 to 5 V.
