Simple IR sensor Circuit

IR sensors are widely used in so many applications. Here i am providing simple circuit to  make IR sensor for smaller applications like Line Following Robot,obstacle detector etc.. and i did some experiments with this small circuit and i will share them with you here.

->Components needed:

    1) IR Tx Led.
    2) IR Rx Led.
    3) 1KOhm resistor.
    4) 10KOhm variable resistor.

-> Circuit Diagram:
   

  

you can use supply voltage 5V or 9V. By changing the variable resistance value you can get the different detection ranges.this circuit is applicable to smaller projects only, it has it's own limitations.








-> Working :

        The IR Tx led will continuously transmit the signal and until IR Rx led is     receiving this signal the output you will be "Low".  If the IR Rx Led is not getting the signal the output will be "HIGH".



-> There are two ways you can work with IR sensors
1) line of site type. means placing IR Tx & Rx Led's opposite to each other.
2) Reflective type. placing the IR Tx and Rx LED's side by side

-> Line of site type:

     picture of the setup.

-> Small Demo of working of this setup

 

     In this demo i am connecting the output to blue colour LED. in this video you can find that by changing the variable resistance you can change the detection range of IR sensor.

> Limitations :
          The ambient light can effect the detection range.


 -> Reflective type:

      This is the picture of the module that i made.

The working of this setup is not as expected. The behaviour of this circuit is different with ambient and dark light.

-> Small Demo of working of this setup

In less ambient light condition:

  






in dark light you will get continuously output as "HIGH" and in less ambient light the change in the output will be less but still the output will be "HIGH" only. this you can observe in the video.

->In presence of ambient light:

     In the presence of ambient light The IR Tx led has no effect on Rx Led. the ambient light will be dominant.but  what i observe is the IR Rx led sensitive to distinguish ambient light and dark light. so in presence of ambient light the Rx Led is working as shadow detector.

 ->conclusions :

     Advantage:

       - you can use this setup in Line following robots. in this application it will work.
         there will be no issues.

         Reason: in line following robot you will place these sensors facing downwards.
         mostly you will draw black line on white surface or  vice versa. which are
         perfect reflector(white) and absorber(black). so you will get good results.

      Disadvantage:

    - This reflective type setup you can't use in dark light.

-> you can use the IR Rx led itself as a shadow detector.

->Demo video:

 

 

here i have discussed about the working of one small IR circuit.there are so many circuits which can improve/give better performances for particular need.

i think the information that i have shared will be useful to someone.

Thank you...

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