Proximity Sensor is a sensor able to detect the presence of nearby objects without any physical contact. proximity sensor often emits an electromagnetic or electrostatic field, or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor’s target. Different proximity sensor targets demand different sensors. For example, a capacitive or photoelectric sensor might be suitable for a plastic target, and an inductive proximity sensor requires a metal target. A proximity sensor adjusted to a very short range is often used as a touch switch.

The maximum distance that proximity sensor can detect is defined “nominal range”. Some proximity sensors have adjustments of the nominal range or means to report a graduated detection distance. Proximity sensors can have a high reliability and long functional life because of the absence of mechanical parts and lack of physical contact between sensor and the sensed object. Proximity sensors are also used in machine vibration monitoring to measure the variation in distance between a shaft and its support bearing.

Types of Proximity Sensors

  • Capacitive Proximity Sensors
  • Capacitive Displacement Sensors
  • Doppler Effect Proximity Sensors
  • Eddy-Current Proximity Sensors
  • Inductive Proximity Sensors
  • Laser Rangefinder Proximity Sensors
  • Magnetic Proximity Sensors (including Magnetic proximity fuse)
  • Passive Optical Proximity Sensors (such as charge-coupled devices)
  • Passive Thermal Infrared Proximity Sensors
  • Photocell (Reflective) Proximity Sensors
  • Radar Proximity Sensors
  • Laser Proximity Sensors
  • Sonar Proximity Sensors