Optical...If im not mistaken.
optical mouse
A PIR Motion sensor detects the minute changes in heat and infrared radiation rather than movement.
Most can detect movement ten feet away, however some can detect twenty or thirty feet.
That would be the laser sensor of the mouse.Wireless mouse tend to have laser sensors and Optical the ones with cord. They utilizes light-emitting diodes (LED) or laser as a method of tracking movement.
A "sensor" is used to detect or measure something; in this case, it would be something to detect or measure gravity.
Because motion sensors sense the movement of light, so if its dark, it cant see.
All sorts of ways but here are a couple. A motion sensor will detect movement and tell the alarm box to ring. The ddors and windows have strips across them that set the alrm off if they are broken
Various ways. Infra Red sensors can be used for alarm systems to detect doors being opened or motion inside the vehicle. Sensors can be used in doors to detect when the door is opened, and trigger the internal light.
You must use a special type of sensor that will detect the components and the properties of a thing.
Till now it is not possible to make eye moment sensor... The scientist of Korea are researching..Try to search in technology review u may get any clue
yes
MAGNETICS. PHOCOUPLERS any other sensor that detect movement.
Infrared proximity sensor.