The difference between Microwave Motion Sensor and PIR Motion Sensor (Passive Infrared Sensor).
Both are used as occupancy sensors or Motion Sensors, but their principle of working is different. The microwave sensor is an active sensor as it emits a microwave signal for detection. PIR sensor is a passive sensor as it senses infrared signals emitted by various objects, including the human body.
Microwave Motion sensor
As shown in the picture, it emits frequency in the microwave region and will analyze the returned/reflected microwave frequency for determining motion.
PIR Motion sensor | Passive Infrared Motion Sensor
PIR sensor houses a pyro-electric sensor, as shown in the Picture-2. PIR sensor generates energy when exposed to heat. Human or animal body radiates energy in the form of infrared radiation. Hence when a human/animal comes in the range of the PIR motion sensor, it receives thermal energy, and hence motion is detected by the sensor.
The following points summarize the difference between the microwave sensor and the PIR sensor.
➨The microwave motion sensor has a higher sensitivity than the PIR sensor.
➨The microwave motion sensor has a higher coverage range than the PIR sensor.
➨The microwave motion sensor has a continuous field of the detection zone, whereas the PIR Motion sensor has a slotted detection zone. Hence PIR sensor may miss out on objects. Therefore microwave sensors are better in security applications to compare to PIR Motion sensors.
➨Microwave motion sensors have a higher false alarm rate compare to PIR sensors.
➨Microwave Motion sensors are slightly costlier compare to PIR Motion sensors.
➨Microwave Motion sensors consume more energy than PIR Motion sensors. PIR Motion sensors consume about 0.8 to 1.0 Watt electricity, and microwave Motion sensors consume about 1.1 to 1.5 Watt.
➨Microwave Motion sensors are suitable for large area security applications, whereas PIR Motion sensors are suitable for smaller and compact premises.