What is an ultrasonic movement detector?

Ultrasonic movement detector is a device that can detect the movement of people or objects in a limited area. It reduces the movement of sound waves in its environment. Some just listen to sounds while others broadcast ultrasonic signals and analyze how they reflect. This type of motion sensor is often used in the home safety system to sound alarm if something moves. When someone enters the room, it can also be used to turn on lights or other devices.

Active movement sensors generate sound waves in ultrasound frequency range, usually around 30 to 50 kilohertz (KHZ). These frequencies are generally inaudible to humans and most animals and do not pass mostly objects. The ultrasonic motion detector emits the cone -shaped sound waves using a quartz converter and listens to echoes. When no objects move in the area, the sound pattern remains and the time required to bounce back. If something moves, the detector feels the level or phase of the returning soundThe waves' education has shifted slightly.

Active ultrasonic movement detector should try to eliminate as much noise or false data as possible. To this end, it often analyzes changes in the frequency of dopplers in echoes and changes in amplitude. This type of detector is quite complex and often includes a programmable microcontroller. On the other hand, the passive movement sensor listens to the suspect sounds like metal scratches or glass breaking. Unlike the active sensor, it does not generate any sound waves on their own.

noise and background movement can often inadvertently cause an ultrasonic movement detector. Birds, insects and wind gusts make it difficult to use as an outdoor movement sensor. Low -cost active detector, such as a typical car security sensor, can only analyze variations of echo amplitude. Ignoring frequency variations can lead to false alarms from this type of detector. Ringing phones and other loud noises of a livingY unintentionally triggers passive movement sensors.

furniture, boxes and other large items can "hide" other objects in the area from an active ultrasonic movement detector. They can also absorb and distort the sounds that are critical to the passive sensor. The peaks of air conditioning units or open windows are often also captured as movement. Some engines and fans generate ultrasonic sounds, which can also confuse movement sensors.

Using an ultrasonic movement detector, which contains several active and passive sensors, can improve results. Some systems combine an ultrasonic sensor with a passive infrared motion detector. Analysis of audio and heat data together often provides a more accurate picture than one type itself.