OVERVIEWWhether you’re building a small robot or using any kind of motors in your projects, it might be useful to know the speed at which your are driving them.In this tutorial we will see how to connect and use an infrared speed sensor based on the LM393 chip.The speed sensor uses a disc with holes (encoder disc) to block the infrared beam, thus by counting the number of times the sensors goes from Low to High we can calculate the number of revolution for a given time period.For our tutorial we