Motion detection can detect infrared waves, i.e. heat waves that radiate from moving objects. When the detector senses an object moving across its field of view especially warmer objects such as people, animals and cars. Lights can also trigger a Motion Sensor. For Motion Sensors which sense Infrared Radiation, lights which quickly change in temperature can cause the sensor to trigger.
A microwave motion sensor uses electro-magnetic radiation. It emits waves which are then reflected back to the receiver. The receiver analyzes the waves that are bounced back. If there is an object moving in front of car, these waves are going to be altered. The microwave detector is able to identify changes from moment to moment. Ideally, the receiver should be receiving the same waves back again and again.
Overall, because of the way that microwave motion sensors work, it can be less sensitive than Motion detection do. In other words, microwave motion will be more accurate and won’t be interfered by the changing light or the shaking trees in front of the cam.