Sensors: A device that detects a physical change in its environment and sends information to another electronic device.
Actuator: A device that causes another machine operate. Basically the ‘mover’.
| Factor being measured | Sensor | Actuator |
| Light | LDR, Photodiode, Photo-transistor, Solar Cell | Light, Display, Fibre-Optics |
| Temperature | Thermostat, Thermistor | Heater, Fan |
| Force/Pressure | Pressure Switch, Strain Gauge | Lifts, Electromagnet |
| Position | Potentiometer, Encoder, LVDT | Motor, Solenoid, Panel Meter |
| Speed | Tacho-Generator, Doppler effect sensor | AC and DC Motor, Stepper Motor, Brakes |
| Sound | Carbon Microphone, Piezo-electric Crystal | Bell, Buzzer, Loudspeaker |
Computer Science Notes 