Check the values for IR emitter and phototransistor used for IR detection

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saurav_sdpl

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I am using a IR emmitter and phototransistor for IR detection.

IR light is emitted via a12V supply and 1.2K registance.
Where as The collector registance of phototransistor is 6.2K biased with 12V supply.

Plz check whether these values are correct for the proper operation.

The reflecting surface i am using is lighting tape used in cars, cut in a triangular shape.

when i am moving the module from the top to bottom of surface i am not able to achieve any variation in voltage sensed by phototransistor.

Wat modifications i should do to overcome this problem
 

Re: photosensing

As I understand you use a corner reflector surface, which has a property to reflect the lihgt exactly to the source direction with minimal scattering. I thing this is not the best surface for a simple anlog measurement you want. A simple white paper with diffuse reflecting will be much better.
Another question. What is the value of the phototransistor collector voltage? For a good sensivety it should be about 6 V at the middle of your sensing range.
 

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