A proximity sensor is a type of sensor that detects the presence or absence of an object or obstacle in close proximity to it without physical contact. It works by emitting an electromagnetic field or beam of electromagnetic radiation, and then detecting changes in the field or radiation caused by the presence or absence of an object. Proximity sensors are commonly used in various applications such as automatic door openers, touchless faucets, mobile devices for screen activation, and industrial automation for object detection.

Read more: Embedded Sensor – Proximity

Real-Time Usage

On Mobile

           This sensor installed on the front of an iPhone 5 next to the earpiece automatically turns off the touchscreen when the sensor comes within a predefined range of an object (such as a human ear) when using the handset.

On Parking Sensor

Ultrasonic parking sensor: Source

Parking sensor on a fender

Type of Proximity

• Capacitive Proximity Sensors
• Inductive Proximity Sensors
• Magnetic Proximity Sensors
• Optical Type
  • Photoelectric
  • PhotoCell
  • Infrared Proximity Sensor (Passive Thermal)
• Ultrasonic Type
• Hall Effect Type

Proximity Sensor Application

• Parking sensors, systems mounted on car bumpers that sense distance to nearby cars for parking
• Ground proximity warning system for aviation safety
• Vibration measurements of rotating shafts in machinery
• Top dead centre (TDC)/camshaft sensor in reciprocating engines.
• Sheet break sensing in paper machine.
• Anti-aircraft warfare
• Roller coasters
• Conveyor systems
• Beverage and food can making lines
• Improvised Explosive Devices or IEDs
• Mobile devices
  • Touch screens that come in close proximity to the face
  • Attenuating radio power in close proximity to the body, in order to reduce radiation exposure
• Automatic faucets

Other Proximity Sensor

PRD-12-8DP Inductive Type

• Buy Link : http://www.autonicsonline.com/product/product&product_id=6

LJ12A3-4-Z-BY-Inductive-Proximity-Senso

• Types NPN
  • Data Sheet : Inductive Proximity Sensor,LJ12A3- 4-Z/BX ,NPN,3-wire NO,diameter 12mm,Proximity Switch
• Type : PNP
  • Data Sheet : Inductive Proximity Sensor Detection Switch PNP Model: LJ12A3-4-Z/BY
  • Specification :
    • A component widely used in automatic control industry for detecting, controlling, and non-contact switching When proximity switch is close to some target object, it will send out control signal.
    • Model: LJ12A3-4-Z/AY
    • Output Type: PNP NC(Normally Close)
    • Detecting Distance: 4mm±10%
    • Theory: Inductive Sensor
    • Wire Type: 3 Wire Type (Brown, Blue, Black)
    • Switch Appearance Type: Cylinder Type, Aluminum Shell
    • Supply Voltage: DC 6-36V
    • Current: 200A
    • Detect Object: Iron
    • Diameter: 12mm
    • Cable Length: 1M/3.3Ft
    • 1 x Inductive Proximity Sensor Switch
  • Price Approximately :340rs (India)

---