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Sensors: Different Types of Sensors

2.   IR Sensor

IR - Infrared Sensor

This device emits and/or detects infrared radiation to sense a particular phase in the environment. Generally, thermal radiation is emitted by all the objects in the infrared spectrum. The infrared sensor detects this type of radiation which is not visible to human eye.
·        Easy for interfacing
·        Readily available in market
·        Disturbed by noises in the surrounding such as radiations, ambient light etc.
The basic idea is to make use of IR LEDs to send the infrared waves to the object. Another IR diode of the same type is to be used to detect the reflected wave from the object. The diagram is shown below.
How IR Sensors work
When IR receiver is subjected to infrared light, a voltage difference is produced across the leads. Less voltage which is produced can be hardly detected and hence operational amplifiers (Op-amps) are used to detect the low voltages accurately.
Measuring the distance of the object from the receiver sensor: The electrical property of IR sensor components can be used to measure the distance of an object. The fact when IR receiver is subjected to light, a potential difference is produced across the leads.
·        Thermography – According to the black body radiation law, it is possible to view the environment with or without visible illumination using thermography
·        Heating – Infrared can be used to cook and heat food items. They can take away ice from the wings of an aircraft. They are popular in industrial field such as, print dying, forming plastics, and plastic welding.
·       Spectroscopy – This technique is used to identify the molecules by analysing the constituent bonds. This technique uses light radiation to study organic compounds.
·        Meteorology – Cloud heights, calculate land and surface temperature is possible when weather satellites are equipped with scanning radiometers.
·        Photobiomodulation – This is used for chemotherapy in cancer patients. This is used to treat anti herpes virus.
·        Climatology – Monitoring the energy exchange between the atmosphere and earth.
·       Communications – Infra red laser provide light for optical fibre communication. These radiations are also used for short range communications among mobiles and computer peripherals. 


Great article

hmm i like it..
hmmm super,i wants more about sensors

Great about sensors.. Time to put this theory into practise
theory into practise..good..please put the by one sensor microcontroller..thanks before..

Thank U For this article

thanks for and all those things


thanks for increase my knowledge

nice one:)


I am little much familiar with sensors and have experience working with IR,SOUND,LDR sensor.

and don't know the mechanism of Smoke sensor. And which kind of sensor are used for car security.

Kindly post about these matters.


thanx and impressive work by site admins...

excellent information   iam satisfied with this

i like thise artical


nice informations ...... great job !!!

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thnks for the article



simply awesome documents for all


Can proximity sensors be used for counting no.of persons entering and leaving the door??

If not which sensors can be used for such application??

please reply..!! thanks in advance

I would like to reference this article. Where can I find the publication details related to it? ex author, date of publication etc


thanks in advance

i am greatful to be a part of engineersGarage thanks for your support and also thanks for this team........always be so happy and never forget to smile.

can i ask ?

is there any kind of sensor that can detect sudden change on its target



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