- When people talk about motion, they are generally referring to how fast an object goes over a determined length of time. In physics, there are different types of motion, as well. And motion can be created by applying force to a given object. The force causes particles to accelerate and essentially change the area around them. How much something weighs can affect how fast or slow the object can go. Much the same way a radio antenna can emit or receive radio waves, a motion detector can send out a signal to know if there are objects nearby.
- There are different types of motion detectors, but they all basically work the same way. Motion detectors are made to register certain information in the air created by objects that speed up or slow down. It compiles those signals into data that must be reflected back into a sensor inside the detector itself. There must, however, be sensors placed elsewhere for signals to get sent to a detector. Using a series of either mirrors or electronic sensors, a basic motion detector, after receiving a signal, will emit a signal or pulse to a nearby computer or camera. In some motion detectors, the whole process takes less than a microsecond.
- Motion detectors all receive and measure information differently. A microwave or radar motion detector works the same way as a radar gun. When a police officer points a radar gun at a moving object far away, that object sends back certain information, which registers in the radar gun as a series of data that is interpreted as signals. Waves have certain ways of behaving, depending on length and size, for example. Microwave motion detectors use waves that are generated along an electromagnetic spectrum, typically radio waves. An infared motion detector can detect changes in movement by using light. It also can detect changes in temperture. Just like electromagnetic waves run along an electromagnetic spectrum, light waves have their own spectrum. Heat and ultraviolet rays are two types of invisible light waves that can be measured by numerous types of infrared sensors. Ultrasonic motion detectors use physical and sound waves, rather than mechanical or electromagnetic waves, like the microwave or radar motion detector.
