Sensor
Electronic device or object capable of detecting real-life conditions and interpreting what it has detected into data that the device can understand. A good example of a sensor is a motion sensor that may be connected to a computer to help detect motion within a building. Other sensors may detect heat, light, radiation and sound.
In the picture to the right, is a Microsoft Fingerprint sensor and reader, a
hardware device that allows you to identify yourself with the computer using
your finger.
Also see: Fingerprint