Colour Detection Circuit

Thread Starter

Mazaag

Joined Oct 23, 2004
255
Hey guys,

I was wondering if there is a circuit that is capable of detecting different colours ( as a voltage or current or something) without using a camera or webcam?

Are there cheap optical "band pass" filters for example that would pass only a specific frequency of light that I could possibly couple to 3 LDRs (RED , BLUE, GREEN) and somehow sum up the voltages or soemething and obtain a specific voltage for a specific colour ?

Thanks guys
 

bloguetronica

Joined Apr 27, 2007
1,372
Hey guys,

I was wondering if there is a circuit that is capable of detecting different colours ( as a voltage or current or something) without using a camera or webcam?

Are there cheap optical "band pass" filters for example that would pass only a specific frequency of light that I could possibly couple to 3 LDRs (RED , BLUE, GREEN) and somehow sum up the voltages or soemething and obtain a specific voltage for a specific colour ?

Thanks guys
You can resort to other solution. Use a dark chamber with three LEDs (red, green and blue) and one LDR. Emmit one light at a time and the LDR will read the reflected light.

You can also use three colour filters in front of the respective LDRs, but you have to make sure they will not pick up other frequencies.

One last solution is to use three LEDs as light sensors (as photo diodes). The LEDs will respond only to the frequency of light that they emit.
 
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