Basically, a ToF distance sensor uses the time that it takes for photons to travel ... See the tried-and-true adapter circuit diagram below. A simple Arduino Sketch for obtaining the measurement data ...

Here is the reference circuit diagram of a simple inductive proximity sensor, wired around the 8-pin proximity detector chip TDA0161. This monolithic integrated circuit (from STMicroelectronics) is ...

Most proximity sensors use an electromagnetic field to sense the presence of a target metal. But there are times when it's necessary to sense nonmetallic materials such as plastics, liquids ...