PIR Motions Sensor ( Pyro Electric Motions sensors) senses Infra Red heat sensor emitted from human body. When the human being moves on, the head waves emiited by their body changes the Infra Red wave gradient, this change is detected by the PIR Motion sensor (also called smart switch) and activates a relay. This relay switches ON / OFF a Light or FAN or Alarm etc.
These sesnors also have builtin LUX( Luminance intensity of light) control switch, according to which it works. The LUX sense can vary from 20 LUX( extreme dark) to 20000 Lux( bright sun light). The Smart switch can be operated as per the need. It can be set to Switch On light only after sunset and switch OFF light after sun rise.
These smart switch also have sensitivity parameter adjustment, so that the relay is not operated by a moving rat or butterfly or cat. It is set in the manner so that a Dog of atleast 20 kg ( similar to the weight of a small child) is required to sense the relay.
PIR sensor can be of many types –
A) Wall Mounted PIR sensor – can sense from 12 meter distance in 120 degree angle.
B) Ceiling mounted PIR sensor – can sense from 3~4 meter in 360 degree 3 meter diameter.
In addition to the above, water proof model, out door models etc are avaibale in variour size and l