Proximity Sensor react to approach towards the proximity with or without contact. Proximity Sensor work on the basis of Sensor Technology. Previously we published about basics of Sensor, which will give you the idea of the technology of Proximity Sensor.
How Proximity Sensor works
Proximity Sensor is used in industrial processes, medical diagnostics, robotics, automobile industry for detecting the position of workpieces and tools, as well as a security measure. On some switches, the proximity sensors and switches are united into a single component.
An important source of interference for Proximity Sensor is direct light from sun, artificial light sources such as fluorescent lamps, welding arcs, flashes etc.
These problem can be solved in many cases by optical modulation. Instead of a constant light, pulses of a predetermined frequency of light is measured. The receiver of Proximity Sensor evaluates only the frequency of these pulses and hides all the superimposed noise components.
Types and examples of Proximity Sensor
Inductive Proximity Sensor : Can work for both ferromagnetic and nonmagnetic source.
Capacitive proximity sensor : They also respond to non-conductive materials.
Magnetic proximity sensor : Typically respond to a magnetic field.
Optical Proximity Sensor : They react to light reflection. Photocells evaluate the interruption of a light beam.
Ultrasound Based : These Proximity sensor analyze the reflection of an ultrasonic signal to an obstacle.
Electromagnetic proximity sensor : Changes the resonant frequency approximation of resonant circuits. They respond to both conductive and nonconductive materials.
Most common day to day usage of Proximity Sensor is on our Cars – cars has the parking sensor, positioning sensor and security alert system and all are based on different kind of technology described above. The parking Sensors specifically uses Electromagnetic and Ultrasonic technology.
The car Security Alert usually uses Capacitive proximity sensor, which responses when some thing or even when high sound beam hits on its particular areas of its body.