When a light fitting has an accompanying PIR sensor, this means that the light will turn on when motion is detected. PIR stands for ‘passive infrared’, meaning the sensor will passively pick up emitted infrared. This is accomplished by a pair of pyroelectric sensors that detects the infrared heat that radiates from people or objects. When one pyroelectric sensor detects a change in the infrared that the other pyroelectric sensor fails to pick up, this activates a switch that in turn activates the light.
Passive infrared sensors can trace their roots back to the 1940s, when an alternative to microwave and ultrasonic motion detectors were in demand to cut costs. This became a reality in the 1970s, with PIR sensors making for a great option thanks to their small size, simple installation, cheap manufacturing cost, however, they did not become a popular choice outside of security alarms until the 1990s. Since then, the technology has become more reliable and the manufacturing costs cheaper, allowing for in-built PIR sensors in your light fittings without greatly impacting the cost of the product.
Our catalogue of PIR sensor light fittings include bulkheads, floodlights, lanterns and wall lights in a variety of wattages, colour temperatures and finishes from leading brands such as V-Tac, MiniSun and Elstead Lighting. We also offer standalone PIR sensors to install on your existing light fittings from brands such Eterna and 4WiZ.
PIR sensor light fittings are used in a host of general and specialist applications, with the two most popular uses being for security lighting and energy saving lighting. Some popular places to find PIR sensor light fittings, both domestic and commercial, include: outside front doors, driveways, swimming pools, patios, smoking areas and much more.
Whilst microwave and PIR sensors are both motion sensors, they each detect motion in a different way. Microwave sensors emit microwave signals across their detection range, with the sensor being triggered based on how long the signals take to return to the sensor. This is different from how PIR sensors function, as PIR sensors search for infrared emitted from heat produced by the objects in its range.
Photocell on the other hand, is not a motion sensor, and is used to detect changes in brightness and light levels. This is accomplished by the resistor and circuitry inside the sensor, which only allows electrical power to flow when low resistance is detected as a result of low level light. The benefit of this technology is that it can provide ‘dusk to dawn’ lighting, meaning regardless of any timezone or seasonal changes, your light will always come on when it gets dark, rather than at a fixed time such as 6pm. As a result of this, it’s not uncommon to find PIR sensors with photocell sensor technology built into them as well. This allows a light fitting to save energy not only on movement but only when movement is detected at low level light.
Most PIR sensors have a switch placed (commonly) at the bottom of the sensor, this switch is usually labelled ‘LUX’ and allows you to adjust the PIR sensor to the exact brightness you want your light to start operating at. As a result of this, to make your PIR Sensor light fitting work during daylight, you simply adjust the LUX switch and set it to your needed brightness value. However, if you do not wish for your PIR sensor to respond during daylight, adjust the LUX value downwards, until you feel it is at a suitable value to start switching on depending on the time of day. Furthermore, using the other switch labelled ‘Time’ or ‘Timer’, you can adjust the amount of time the light will remain on after the PIR sensor has been triggered.
The range and angle of a PIR sensor varies from product to product, but generally, the detection range will be between 3m-12m and the detection angle will be between 100°-180° degrees, however smaller and greater ranges are available. Due to the varying ranges of PIR sensors, it is important to identify the exact area you require to be illuminated and ensure your purchased PIR sensor matches the distance required. If you’re unsure what PIR sensor light fitting you require, feel free to call our friendly Sales Team on: 01473 716418.