Proximity sensor

Proximity Sensor

The proximity sensor is a notable example of sensor technology, used to detect the existence of nearby things without any physical touch.
This can be achieved by using Electromagnetic field or radiation which is distorted by objects.
Proximity sensors are highly reliable due to the presence of metallic parts and no physical contact.
Proximity sensors are available in the high range of frequencies as well as in the low range according to the objects.
Let’s talk about its working;

Working of Proximity Sensors

Proximity sensors working is based on the condition of the transistors and existence of the objects or target.
The standard target should have a thickness of 1mm with a smooth and flat area and made with steel.
If the size of the target is greater than the standard size then no change in the sensing range is observed but if the target size is less than the standard size than the decrease in sensing range is observed.

Nowadays, Proximity sensors are available in almost every smartphone devices and work with the help of infrared radiation(IR) which is unseen from normal human eyes.
Its working is very simple, infrared radiation LED emits IR radiation which bounces back by any nearby objects and radiation is detected by the receiver. But its intensity varies based on the distance between the object and the IR receiver. If very high intensity is observed means obstacle is very close.

Features of the Proximity Sensors

For better understanding let’s explore its qualities:

1. None contact detection system

Detect nearby objects or obstacles without touching them physically. Therefore, the Proximity sensor does not cause any types of damage to the object.

2. Positioning with High Precision

Proximity sensors are composed by a semiconductor circuit which provides excellent precision in the positioning of the object.

3. High Response Speed

Proximity Sensors provides a very high response speed rate by comparing the electric field or magnetic field strength.

4. Independent of the surface conditions

The proximity sensor can detect the physical existence of an object but its result is unaffected by its surface conditions.

5. Long-lasting service

Proximity Sensors are totally prepared by the semiconductor devices which are fixed.

6. It can be used in water or oil systems

Types of Proximity Sensor

The proximity sensors are available in different varieties as per their detection technology. Some of them are given below:

1. Inductive Proximity Sensor


  • This sensor operates under Electromotive Force (EMF)
  • Sensing Range: 4-40mm
  • Target Material: Iron, steel, copper, aluminium etc.

2. Photoelectric Proximity Sensor


  • Used for long-range and large or small target detection.
  • Sensing Range: 1-60mm
  • Target Material: Silicone, plastic, paper, metal etc.

3. Capacitative Proximity Sensor


  • Used for close-range detection of non-ferrous materials
  • Sensing Range: 3-60mm
  • Target Material: liquids, wood, graduates, plastic, glass etc.

4. Ultrasonic Proximity Sensor


  • Used for long-range detection of targets with various surface properties like colour and reflection etc
  • Sensing Range: 3-30mm
  • Target Material: Cellophane, foam, glass,
  • Liquid, powder etc.

Applications of Proximity Sensors

Proximity sensors have various applications. Some of them are given below:

  • It is hugely popular in detecting objects.
  • In different projects of engineering.
  • In the parking lot
  • Counting objects in conveyor systems
  • Enormous application in smartphones etc.
  • Inspect high-speed movement
  • In safety and security

What is a proximity sensor on a cell phone?

In phones, it is used to detect when users face is close to the phone screen. During the phone call, you have observed that your phone screen automatically switch when you hold your phone close to your ear. All of this is due to Proximity Sensors and it prevents any errant button-pressing issue.

IR Proximity Sensor and Price

IR Proximity Sensor

Price: Rs. 250

This one is used for obstacle sensing, line sensing and as an encoder sensor. An LED is used to detect.


  • Sensing Range: 10-15cm
  • Sensor Output: +3V
  • Digital Output: 1 or 0
  • LED indicator for SIG and PWR
  • Interface like: ARDUINO, AVR, 8051, PIC, ARM,  MSP430.
  • No. Of Pins: 3(OUT, VCC GND)

Leave a Comment