Sensors, Actuators, and Circuits in Robotics

There are a number of sensors like proximity, infrared, temperature, and pressure that one encounter often during daily living. Human body is equipped with five different types of sensors: eyes that detect light energy, ears that detect acoustic energy, tongue and nose that detect certain chemicals, and skin that detects pressure and temperatures. The eyes, ears, tongue, nose, and skin receive these variables from the environment and transmit signals to the brain which controls the response. For example, when you touch a hot plate, it is your brain that informs you it is hot and, therefore, you take your hands off it. In this case, the skin works as the sensor, brain as the controller, and hand as the actuator.