sensor
//ˈsɛnsər//
Noun
sensorSingular
sensorsPlural
1
A device that detects or measures a physical property and records, indicates, or otherwise responds to it.
The motion sensor turns on the lights automatically when someone enters the room.
2
A component in electronic systems that converts physical stimuli such as heat, light, sound, or motion into electrical signals.
The motion sensor detects movement and turns on the lights automatically.