Motion sensor – What is the difference between a PIR and a microwave sensor?

Summarize

PIR sensor detects temperature differences using infrared rays
The microwave sensor measures the signal to detect echo time movement
The PIR sensor is sensitive to temperature changes, the microwave does not
The microwave sensor works more widely, even through walls
Motion sensors save energy and improve safety

What is the difference between a PIR and a microwave sensor? A motion sensor can use microwave or PIR sensors and here we briefly look at the pros and cons and differences.

What is a motion sensor?

A motion sensor, as the name suggests, is a device that can be used to detect when someone is approaching, causing for example lights to turn on when they are needed. They can be used to reduce energy bills by turning off lights when no one is around, or motion sensors can be used as a security measure, turning on lights and alerting a smart app when someone approaches, for example by flashing a light inside.

What is the difference between a PIR and a microwave sensor?

So there are motion sensors on the market that use microwave and PIR sensors, but what is the difference between PIR and microsensors?

PIR motion sensor

PIR (Passive Infra red) sensors detect warmth They do this by measuring the ambient temperature in a room using a series of infrared beams. When even a single infrared beam detects a temperature difference, the sensor is activated and turns on the lights. When all infrared rays see the same temperature, the lights go out.

Microwave motion sensor

Microsensor, or Microwave. Do not mix with the microwave, as this will not heat the food. These motion sensors transmit microwave signals and measure the time it takes for the signal to be reflected back to the sensor. The reflection is called an echo. The echo time is used to calculate the distances to all stationary objects in the detection zone. This allows a baseline to be established against which to compare. A person entering the detection zone causes a disturbance in the microwave signal, which changes the echo time and turns on the lights.

History of motion sensors

Who invented the motion sensor and when did they become widespread? Motion sensor technology has been developed on the basis of radar technology,

PIR History

The basis of the passive infrared sensor (PIR sensor) was invented as early as the 1950s, but its use only became widespread in the 1980s, when Marcel Zueblin patented the first consumer product that used motion to control lighting. PIR sensors are widely used in security systems, lighting and other applications where motion detection is required.

The first motion sensor attached to a wall and connected to a power outlet. — The first motion sensor was developed by Marcel Zueblin

History of the microwave sensor

Microwave sensors were initially used mainly in military and security applications, but later their use has expanded to other applications such as automatic doors, camera systems and motion sensors. The invention also emerged in the United States, where Samuel Bagno was the developer of the microwave sensor. He invented the first motion sensor in the 1940s, using technology developed during the Second World War. Using his military knowledge of radar, Bagno developed a device that used ultrasonic waves and the Doppler effect to detect movement in a room. He utilized the device in the 1950s by developing the first burglar alarm.

Samuel Bagno and the first security alarm and motion sensor — Samuel Bagno 1950 and the first alarm and motion sensor image source Getty Images Dave Mathias

If you are more interested in the history of motion sensors, you can read more about the history of motion sensors here.

PIR vs. microwave sensor – functional differences

When choosing a motion sensor, you should consider the following:

	PIR	Microwave
Sensitivity	Sensitivity poor in hot weather	Uniform detection at all temperatures.
Coverage	90°	360°
Observation	Not always detected if you walk straight towards it	Works even through a wall

Since a PIR sensor detects motion based on differences in heat, the ambient temperature can greatly affect its sensitivity. This limitation must be taken into account if you are looking for motion sensors for outdoor lighting. Extreme outdoor temperatures can have a significant impact on the efficiency of equipment. On the other hand, microwave sensors can be problematic in smaller indoor spaces because they are capable of detecting motion through walls. This can cause issues if there is movement on the other side of the wall. However, the problem can be reduced by installing the microwave sensor in an enclosure and aiming it appropriately.

A motion sensor is often much more

Motion sensor + twilight sensor = light only comes on in the dark

Virtually all motion sensors on the market also have a light sensor. In other words, the operation of a motion sensor is also controlled by a photocell, which, thanks to its easily adjustable settings, can be configured to react to different lighting levels according to the desired use. The light sensor is designed so that you can adjust the screw so that the motion detection is always on even when it’s light out or only when it’s dim or dark.

Sensitivity adjustment in microwave sensors

Microwave sensors also typically include a sensitivity adjustment that can be used to reduce detection through walls. The adjustment may be a DIP switch or a stepless control.

motion and light sensor with microsensor — Sensitivity and light level adjustment in the microsensor

You can access LedStore’s entire motion sensor selection here. Explore the selected motion sensor products below: {{collection items=”Liiketunnistin mitä eroa on PIR ja mikroaaltotunnistimilla”}}

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FAQ

1. What is the difference between PIR and microwave detectors?

A PIR sensor (Passive Infrared) detects infrared radiation generated by temperature changes in the environment. A microwave sensor, on the other hand, emits microwave signals and measures their reflections to detect motion. The PIR sensor is effective indoors, while the microwave sensor offers wider coverage and can detect motion through obstacles.

2. Which sensor is best suited for outdoor lighting?

A PIR detector is usually recommended for outdoor lighting, as it detects movement nearby without unnecessary alarms. Microwave detectors can be used over wider areas, but their sensitivity can cause false alarms, for example due to moving branches.

3. What are the advantages of a microwave sensor?

The microwave sensor offers a wide operating range and can detect movement even behind obstacles such as glass or walls. It works well in environments with little temperature variation and is effective for covering large areas.

4. What are the possible disadvantages of microwave sensors?

Microwave detectors can be too sensitive and cause false alarms, for example due to moving trees or pets. They also consume more energy than PIR sensors.

5. How to choose the right motion sensor?

The choice should take into account the installation environment and needs: a PIR detector is suitable for small indoor and outdoor areas where accuracy is required, while a microwave detector is better for large areas where obstacles may prevent the detection of movement.

Janne Halttu Owner

LedStore.fi entrepreneur who has built 4 detached houses and renovated several properties. 20 years of construction experience has given me a lot of knowledge about structures, and electrical work for several houses. I have worked with LED lighting for over 10 years. I am an expert in Led lighting, I write articles and I am a lighting designer. I often help clients with electrical and structural issues related to lighting and house construction.

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