Microcontrollers are small boards that allow the interaction of computers with the real world, going beyond mouse, keyboard and video camera. They normally run in the Mega Hertz frequency range (which allows more than enough precision for behavioural paradigms and psychophysical tasks) and have a wide range of digital inputs and outputs, so one can send and receive TTL pulses. They also have analogue inputs and outputs, which allows the reading of sensors (such as temperature, infra-red, accelerometers) and controlling of motors or the intensity of a LED. All of this is achieved by running custom written code (one can find several examples of code on the internet to get started).

"File:Mbeb microcontroller and pin-out.jpg"by Nbauers is licensed under CC0 1.0