Infrared radiation can be found everywhere, from natural phenomena, including forest fires and lava flows, and body heat emitted from humans, to more artificial creations, like incandescent light bulbs, remote controls, and infrared lamps. Motion detection is one area where infrared radiation can be of use. Passive infrared (PIR) detection technology can be applied to identify any alterations that occur in the infrared radiation within a location. Thanks to this capability, PIR detectors can be utilized in motion detection systems, like automatic lighting and security alarms. Today, we’ll look at PIR detectors in more detail and uncover how these sensors work.

Explaining PIR Detection

What is a PIR Detector?

PIR detectors are sensors that can recognize infrared radiation. Although they do not produce any energy, they can passively identify the infrared radiation that’s generated from other objects. When a change occurs in the infrared radiation of an environment, the PIR detector is able to recognize it. These alterations usually relate to the differing temperatures of the object and the location. So, let’s say a warm object, for instance a human body, starts moving around an area. If it’s in the view of the PIR detector, the detector will be able to sense that something has changed. This is because there will be a variation in the infrared radiation. The location will have a lower temperature than a warmer object. Therefore, the location will have less infrared radiation compared to the object.

Arrangement of PIR Detectors

PIR detectors are made up of the following components that identify the infrared radiation and transform it into the electric signal needed for motion detection:

• Thermopile: Utilized to quantify temperature changes, a thermopile is a type of sensor which is composed of various thermocouples that are linked either parallel or in a series. When applied to a PIR system, a thermopile sensor can transform infrared radiation into an electrical signal. Its main objective is to identify any alterations that occur with the infrared radiation, using its thermocouples to pinpoint any temperature changes, which can indicate movement after its electrical voltage has been processed. 
• Fresnel Lens: A Fresnel lens is applied to PIR detectors to improve location coverage. It’s made of plastic and has concentric ridges that hone the infrared radiation in on the thermopile sensor. With a fresnel lens concentrating the infrared radiation onto the thermopile, it will be able to identify even the most minute movements. 
• Infrared Filter: The filter can ensure that only infrared radiation wavelengths can pass through and meet the thermopile sensor. It can prevent alternative radiation types, like UV or visible light, from getting through, making sure that relevant thermal signals are what cause the detector to respond. This component can help to enhance accuracy and lower false triggers.
• Processing Circuitry: Electric signals produced from the thermopile can be changed into data through processing circuitry. It can ensure the electrical signals are changed into an output.
• Housing: The components are protected within a protective enclosure.

How PIR Detectors Function

PIR detectors can identify movement by watching for any alterations that occur with the infrared radiation. These detectors contain a thermopile sensor that takes in the infrared radiation of a location. Once a warm object enters that area, and moves about it, this causes the infrared radiation to experience a change. The alteration is noted by the thermopile and its thermocouples produce an electrical voltage, which occurs if they experience heat. This is when the detector’s circuitry comes into play. It’s able to process the voltage change, increasing the signal and ascertaining whether movement has taken place. Should it be decided that there is movement, the PIR system is set off, undertaking actions like switching on lights or causing alarms.

Benefits of PIR Detectors

Security is something that can be offered by PIR detectors. They can be applied with other security technologies or they can be utilized by themselves for identifying intruders. PIR detectors can also be used to initiate alarms or lights to ensure any trespassers are deterred from entering.

An additional advantage of using PIR sensors is their reduced false alarm rates. They’re unlikely to produce a false alarm, especially in comparison with microwave and ultrasonic detectors. Their robust accuracy ensures that they’re not activated without cause and they can preserve their energy. Finally, these devices can help to ease activities in daily life. They offer simple installation and take away the requirement of a light switch, ensuring places like staircases and hallways deliver automatic lighting when someone enters a space.

Make Every Movement Count With PIR Detection

No matter where you need PIR detection, its effectiveness in motion detectors cannot be denied. Take control of your security with the detectors from Dexter Research Center. Thermopile detectors can be applied to PIR systems, as the sensitivity of thermopiles plays a key factor in identifying infrared radiation. Our detectors offer extensive benefits, including high levels of sensitivity and a robust lifespan, being the devices you need to keep an attentive eye over a location. We can provide you with more information about the capabilities of our thermopile detectors. Utilize our experience and knowledge to find a quality detector that can identify motion with ease.