Proximity detector

A proximity detector is a type of sensor that has the ability to detect the presence of nearby objects and people without the need for physical contact.

Typically, a sensor emits an electromagnetic field, or a beam of electromagnetic radiation, and looks for changes in that field or return signal. The object or person that is sensed is often referred to as the "target." A signal is then sent to a receiving device, alerting whoever set up the device that there is movement in a specific area. The detector itself can also be configured to emit a sound or a particle beam when movement is detected.

Technologically speaking, this type of detection device is highly reliable and long-lived, due to the absence of mechanical parts and lack of physical contact between the sensor and the sensed object. This also makes them easy to disable or destroy.

Types of Sensors:

• Doppler (sensor based on doppler effect)
• Optical (such as a retinal scanner)
• Radar (the use of radio waves to determine distance, direction, height and speed of an object/person)
• Sonar (use of sound to navigate, measure distance, and communicate or detect objects)