Occupancy Sensors Deliver Lighting on Demand

Sensors Technology

Occupancy Sensors Deliver Lighting on Demand

Occupancy Sensors Deliver Lighting on Demand

Sensors are wonderful things. Many of us have someone at the front door who automatically turns

on the lights when we get home late at night. This ensures that no one is lurking in the shade and

gives us enough light so we can see to open the door. In the home-grown, sensors afford assistances, counting handiness, sanctuary, and charge reserves (by partaking sunlit only when desired). In commercial buildings, the same benefits are multiplied many times over.


Lighting can account for up to 40% of the energy used in commercial buildings, and the cost of

that energy increases from year to year. One of the easiest ways to reduce energy consumption

and lower costs (and emissions) is to turn off lights when they are not needed. There are manual

light switches so people can turn lights on and off. Most of us are good at lighting candles, but we

often forget to turn them off when we leave a room.

Control lighting and HVAC

This is where presence devices come in. Originally designed for use with security systems,

presence sensors have been refined and improved to control lighting and HVAC in commercial

and residential areas. These sensors perceive movement within a detailed area and afford

expediency by repeatedly spinning on the lights when somebody arrives. They also reduce

costs and energy consumption by turning off the lights shortly after the last occupant has left.


Using presence sensors to turn off lights when areas are vacant help reduce energy waste and

costs by 35% to 45% (according to the California Energy Commission).


Most devices are configurable and can be adjusted to the required levels of sensitivity and

accuracy. This helps prevent false shots, which can be caused by things like air movement

from HVAC ventilation ducts and hot air movement in front of a sunny window. Some sensors

also allow you to set time delays between the sensor that detects lack of occupancy and the

lights go out (typically 10-15 minutes).

Occupancy device are the best suit for areas where people spend varying amounts of time and

often forget to turn off the lights when leaving, such as meeting rooms and private offices.

There are two main types of presence sensors used for lighting and building automation systems:

passive infrared (PIR) and ultrasound.

Passive infrared sensors

lifeless infrared sensors (PIR) detect occupancy by passively measuring infrared radiation

emitted by visible objects. Motion is detected when an infrare source (such as a person) passes

in front of another infrared source with a different temperature (such as a wall). PIR sensors

respond to changes in heat patterns created by the moving person and turn the light on and

off accordingly.


A curled faceted lens expresses the ground of understanding as a fan-shaped succession of

perpendicular and straight distinguishing “pinecones” expected from the instrument. The

farther an occupant is from the sensor, the wider the space between these cones and the

greater a movement must be to activate the device.


PIR sensors are highly resistant to false shots, but are strictly sight and cannot “see” around

objects or on partitions. These sensors are ideal for areas with little or no obstacles, such as

small offices and meeting rooms.

Aerospace Ultrasonic Test Equipment Basics


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