Sensors
There are four types of sensors used in motion detectors spectrum:
- Passive infrared sensors (Passive)
- Senses body heat. No energy is emitted from the sensor.
- Ultrasonic (active)
- Sends out pulses of ultrasonic waves and measures the reflection off a moving object.
- Microwave (active)
- Sensor sends out microwave pulses and measures the reflection off a moving object. Similar to a police radar gun.
- Tomographic Detector (active)
- Senses disturbances to radio waves as they travel through an area surrounded by mesh network nodes. Has the ability to detect through walls and obstructions.
Read more about this topic: Motion Detector