PID controller

In the simplest terms, a PID controller is something that helps you keep something at a certain amount. Imagine you want to keep your room at a certain temperature. You would set a goal temperature, like 75 degrees. Then, you might use a PID controller to automatically keep the temperature in the room at that exact temperature. Once it reaches 75 degrees, the PID controller would make the room cooler, and once it goes too low, it would make it warmer – all automatically!