How to make a DIY colour sensor?

[Js_Ong]

hi, can I make myself a colour sensor? I want to sense Red or Green colour. If I use a Red and Green LED as transmitter and two light sensor as receiver, could this idea be implemented? The distance to sense will be not a matter. thanks.

 

[qaseemali]

coloursensor

A somewhat crude Color sensor can be implemented using a simple White led and an LDR. Check the resistances when the white led is reflected back on to the LDR by Red and Then by Green.
The output of the LDR can then be given to a comparator which gives you a low or a high. The differential inputs can be generated using a resistor bridge with the LDR.