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Microwave Sensor vs PIR Sensor

There are several motion-sensitive lights on the market right now, with Martec’s range leading the industry. Motion detecting lights help reduce wasted energy around homes and businesses as they turn off when no one is around. Motion sensitive lights are also great security, especially for homeowners. And security lights are more important now than ever before. However, many people don’t realise there are two different kinds of motion detection options on the market. And they both work in very different ways. By knowing the difference between PIR sensors and microwave sensors, you can make the right choice when looking for new lighting. Today we are going to discuss the difference between microwave and PIR sensors, as well as the benefits of motion sensor lighting.

The Benefits of Motion Sensor Lighting

Of course, the most common use for motion detecting and sensitive lights is as security lights. They are installed in gardens and entryways for homeowners. They’re also common in car parks and building sites. These floodlights can light up as soon as they detect motion. This not only provides security, and helps prevent people from creeping around your home, it also improves safety. No more fumbling around in the dark, trying to find steps or fumble with light switches when carrying bags and armfuls of groceries.

What Are PIR Sensors?

PIR means “passive infrared”. Lights that use PIR sensors, utilise infrared sensors to constantly monitor everything within range. These sensors are generally made up of two small slots. Think of them as “eyes”. When nothing is moving in front of the sensor, the “eyes” pick up the same amount of infrared radiation. However, when a warm body enters the sensor’s field of view, one of the “eyes” will pick up the movement before the other. This is because the two different parts of the sensor are picking up different heat signatures so the sensor knows there is something moving across it’s field of view. This is what triggers the light to turn on. And, when the warm body leaves the sensor’s field of view, the heat signature drops, so the sensor returns to normal and turns the light off.

PIR sensors only detect heat signatures, so they aren’t usually triggered by inanimate objects being blown across their field of view. This not only makes them good security light, they won’t trigger whenever a leaf blows across a path or a branch moves in the wind. They will trigger for animals and wildlife, though, so that is something to consider if you have pets.


Unlike PIR sensors, microwave sensors work similarly to sonar. These sensors send out constant microwave signals into their environment. They then measure how long it takes for the signal to bounce back to the sensor. When something moves within the detection zone, this disrupts the signal, slightly delaying the amount of time it takes to reach the sensor. The microwave sensor recognises this delay and triggers the light to switch on.

Unlike PIR sensors, microwave sensors are far less reliant on having a direct line of sight, this makes them better for large or awkwardly shaped spaces. Some highly sensitive microwave sensors can emit a signal that can even travel through glass and thin walls.

PIR vs Microwave Sensors

PIR sensors are neither objectively better or worse than microwave sensors. Both sensor types have their own advantages and are better for different spaces and tasks. Lights that feature PIR sensors are generally best for use as security lights. They only pick up movement from living things, meaning they will give fewer false alarms. On the other hand, microwave sensors can be adjusted to only pick up movement from human-sized movement from human-sized objects, however this is generally done in the factor before the sensors are installed in the lights.

Location is important with PIR sensors, as the target needs to pass through their field of view to be detected. This makes them ideal for clearly defined areas, like corridors, walkways, entryways and alleyways where they can’t be avoided.

Microwave sensors, however, don’t need a specific line of sight to detect movement. This makes them better suited to odd shaped rooms and spaces, with a lot of obstacles. They also don’t rely on heat signatures, so they are more reliable in hot areas where a PIR sensor might not be as effective. Microwave sensors are also much more sensitive, which makes them suitable for times when you need to detect very fine movement. However, in an open space or around homes, they may be inappropriate as they can be triggered by blowing leaves, moving branches and other small objects. For garden and home security, a PIR sensor light is far more efficient and effective.

Looking for the best in sensor lighting? Martec has a wide range of PIR and microwave sensor motion lighting. No matter the application, we have the right options for you!