|Noun||1.||sensor - any device that receives a signal or stimulus (as heat or pressure or light or motion etc.) and responds to it in a distinctive manner|
|(hardware)||sensor - An electronic device used to measure a physical
quantity such as temperature, pressure or loudness and convert
it into an electronic signal of some kind (e.g a voltage).
Sensors are normally components of some larger electronic
system such as a computer control and/or measurement system.|
Analog sensors most often produce a voltage proportional to the measured quantity. The signal must be converted to digital form with a ADC before the CPU can process it.
Digital sensors most often use serial communication such as EIA-232 to return information directly to the controller or computer through a serial port.