Essay On Motion Sensing

I. Abstract
Motion sensing is the technique in which a system detects a change in position of an object with respect to its surroundings. This paper gives an overview of motion sensors and some of the applications that have been studied by scholars.
II. Introduction
Motion sensing is the process of detecting a change in position of an object with respect to its surroundings, or, change in the surroundings with respect to the object.
Motion can be sensed in several ways:
i. Infrared sensing using passive or active sensors ii. Vibration sensing using seismic sensors iii. Sound sensing using acoustic sensors and microphones iv. Optics sensing using video camera systems
Motion sensing is classified into following types:
i. Local motion sensing:

Problems faced
Motion sensing, though a breakthrough technology, faces several challenges as of now; which can be stated as follows:
a) Sensor Obstruction: if the sensor is blocked, it cannot detect any motion within its range. This blockage could be as trivial as an insect resting on the motion sensor.
b) Dirty Sensor: sensors exposed to external environment are highly prone to becoming dirty, which has the same effect as a blockage.
c) False Motion: any type of motion could trigger an alarm. So if a curtain blows or a window shuts close due to a windy day, the sensors detect that and can raise an unwanted alarm.
d) False heat signature: instead of being triggered by natural motion, some sensors are triggered by change in temperature of the surroundings. In such a system, if there is a fireplace, the alarm could trigger unnecessarily.
e) Battery life: life of a motion sensor is entirely dependent on the batteries, in case they are powered by them.
f) False daylight: on several security lights, sensors save on battery life by switching off when the light in a given area approximates daylight. So if sometimes, at night, a security light fails to get switched on, it could be because of another source of life triggering the shut