Hello friends! In this tutorial, we will study an infrared sensor built around a 555 timer. We will separate the design into a transmitter that produces infrared light and a receiver that responds when that light reaches it. This is a useful starting point for a beam detector, a simple object detector or an experiment in optical communication. We will also examine the original hand-drawn circuits, explain their timing and current calculations, and identify the details you should resolve before assembling them. A simple infrared detector does not automatically measure distance. Its response depends on the emitter, receiver, alignment, ambient light and the object in the beam. Keeping those limitations clear will make your experiments much easier to interpret. Figure: Original infrared trans ...