TechInfoPost: Proximity Sensors..

Overview

        We all have heard about proximity sensors being used in our smartphones; however trivial be the smartphone, it does consist of a proximity sensor. Furthermore, most of us who drive cars would know regarding the proximity between objects and its sensor since a parking mechanism implements proximity sensors to detect the distance between your car and the object behind. Therefore in this blog i'll be writing about the proximity sensors in general, its working and its applications.

Need for proximity sensors?

       A proximity sensor is an element of the sensing family that is able to detect and retrieve certain information regarding the presence of an object; what's fascinating about this is that, a proximity sensor retrieves data without physical contact with the object. 

      Being able to detect an object without physical contact opens a whole new realm of possibilities in the field of sensing and its equipments. First of all, the need for a sensing device arrises from the very necessity to measure distance between two objects. In order to measure distance without any physical connections between them, a type of sensor came to rise known as the Proximity Sensor.

How does a Proximity sensor work??

There are two formats/range of sensors:

• Proximity sensor using Electromagnetic field: These type of proximity sensors often have an electro-magnetic field surrounding them to a certain proximity. The detection of object, distance between them, etc is all done based on the changes in the electromagnetic field that occurs due to the interference of an object in the field.

• Proximity sensor using Electromagnetic radiation: These type of proximity sensors usually emit certain electromagnetic radiation (Infrared for example) and measure the changes in the signal that bounces off the target object. Applications of these kinds of sensors extends to sonars, radars and military applications like target acquisition systems.

Applications of Proximity sensors:

• Car parking sensors: These are proximity sensors designed to alert the driver of the obstacles while parking a vehicle. These systems en-corporate Ultrasonic Proximity sensors which basically emits acoustic waves in the ultrasonic region of sound waves (making it silent for human ears!) and the time taken by the wave to bounce back is measured. Then on, the logic is as simple as speed = distance/time. A beeper is attached to this sensor to warn the driver as the distance grows closer between the objects.

• Ground Proximity warning sensors (GPWS): Used mainly in aviation systems to keep track of the altitude and mainly of immediate obstacles (mountains, peaks, structures etc) if the plane runs into one. It is also defined as the Terrain Awareness Warning System TAWS because it warns the pilot of the changing terrain.

• Counter air- Defence: In other words, also known as RADAR - RAdio Detection And Ranging. This particular invention has shaped the history in numerous ways. It was during the World wars that both fronts were heavy into the arms race and needed a system that could track down hostile aircrafts to be shot. Thus came the rise of radars. RADAR works on similar principles as that of a parking sensor; one or the other form of electromagnetic beam is emitted randomly and when it hits an aircraft, beam bounces back, and the location, distance (of aircraft) from radar is discerned from the returning wave.

• Proximity sensors on smartphones: smartphones have proximity sensors in the area adjoining the front speaker that enables you to do certain operations. Most important of all, Its primary function is to disable screen operations when you dial/receive a call and place it on your ear; this has made it easy to use touch screen smartphones without any fear of call being ended abruptly. These proximity sensors usually use Optical or Electrical type of Proximity sensors.