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What is a PIR Sensor and How Does it Work?

In the realm of home security, PIR sensors play a crucial role in detecting motion and ensuring your safety. PIR stands for Passive Infrared Sensor, and despite its technical-sounding name, its principle is quite simple yet effective.

At Midland Alarm Services, we believe in empowering our clients with knowledge about the tools that safeguard their homes so they can make a decision about what setup might be best for their home. So, let's dive into the world of PIR sensors.

Understanding PIR Sensors:

In a nutshell, a PIR sensor detects infrared radiation emitted by objects in its field of view. This includes heat radiation emitted by humans and animals. But how does it distinguish between harmless heat sources and potential threats?

How PIR Sensors Work:

Inside a PIR sensor, there are two main components: a pyroelectric sensor and a Fresnel lens. When there's no motion, the sensor detects the infrared radiation from the background environment, establishing a baseline.

When a person or an object moves within the sensor's range, it detects a change in the infrared radiation pattern. This change triggers the sensor to send a signal to the security system, alerting it to the presence of motion.

Benefits of PIR Sensors:

●      Accuracy: PIR sensors are highly accurate in detecting human and animal movement, minimising false alarms.

●      Energy Efficiency: They only activate when motion is detected, conserving energy.

●      Reliability: PIR sensors work well in various lighting conditions, making them reliable for indoor and outdoor use.

Pet-friendly PIR Sensors

Animal-friendly PIR sensors are designed to distinguish between human motion and the movement of pets or other animals, reducing the likelihood of false alarms. These sensors utilise advanced technology to detect and filter out the unique patterns of animal movement, ensuring that the alarm is only triggered when a genuine threat is detected. The sensitivity of these sensors can be adjusted to meet the needs of your unique family’s needs and setup.

One common feature of animal-friendly PIR sensors is the use of dual-element detection technology. This involves two separate sensors within the device, each sensitive to a different range of infrared radiation. By analysing the signals from both sensors simultaneously, the sensor can differentiate between the heat signatures of humans and animals.

Another approach used in animal-friendly PIR sensors is the incorporation of advanced algorithms that analyse the characteristics of motion detected by the sensor. These algorithms can distinguish between the erratic movements of animals and the more deliberate and predictable movements of humans, allowing the sensor to ignore pet activity while still providing reliable security coverage.


Integrating PIR Sensors with Your Security System:

At Midland Alarm Services, we use a variety of different PIR sensors by our trusted supplier HKC to fit the needs of our customer’s homes. Here are the main PIR products we use and what their role is:

●      Wireless RF-PIR - This device has exceptional wireless range and performance. It also has a pet-immune feature and a 15m detection range.

●      This product is often used throughout the home in areas such as living rooms, studies, hallways and landings so that motion can be detected in multiple areas of the house in the event of a break-in.

●      Because of the wireless capabilities, we often add these PIRs to several rooms when upgrading customers from a  wired system to a hybrid wireless system.




●      Dual-Tech PIR - These dual-tech motion sensors have exceptional range so work brilliantly even in tricky spaces.

●      They are designed for harsher environments making them ideal for garages.





●      Camera PIR - These camera PIR cameras are designed to only start recording when motion is detected while the alarm is set. For customers on our SecureComm app, in the event of a break-in you will receive instant image verification to your phone.

●      Because the camera only springs into action when needed and because we use remote/ self monitoring systems (as opposed to third party monitoring), you don’t have to worry about the thought of someone in a call centre potentially being able to see into your home.


PIR sensors are a cornerstone product in home security and the silent guardians of your home, constantly vigilant and ready to detect any suspicious activity. Understanding how they work empowers you to make informed decisions about your home security.

If you’re ready to enhance your home security and want to discuss what setup would be best for your home, contact Midland Alarm Services today for a free, no obligation and no hard swell quote and let us be your trusted partner in protecting what matters most.

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