Circuit Color Detector

This color detector circuit can detect eight colors, it's blue, green and red (primary colors), magenta, yellow and cyan (secondary color), and black & white. The series is based on the fundamentals of optics and digital electronics. The color of the object that needed to be detected must be placed in front of the system.

  

Note:

• Potmeters VR1, VR2 and VR3 can be used to adjust the sensitivity of ldrs.
• Common ldrs ends must be connected to the positive supply.
• Use a good quality light filters.

Rays of light reflected from the object will fall on the three convex lenses that remain in front of three ldrs. A convex lens used to gather light rays. This helps to increase the sensitivity of ldrs. Blue, green and red glass plates (filters) are fixed in front LDR1, LDR2 and LDR3 respectively. When the light reflections from objects falling on gadgets, colored plate glass filters to determine which of the ldrs will be triggered. The series just using AND gates and NOT gates.

When the primary color light rays fall on the system, the glass plate in accordance with the basic colors that will allow certain light to pass through. But the other two glass plates will not allow any light through it. So only one LDR will trigger and gate outputs in accordance with the LDR will be a logic 1 to indicate the color of it. Similarly, when the secondary colored lights fall on the system, two major glass plate corres-ponding to a mixture of colors that will allow a light through it while the rest will not allow any light rays to pass through. As a result two of ldrs can trigger and gate outputs corresponding to this will be a logic 1 and indicate that the color of it.
When all ldrs get triggered or remain untriggered, you will see black and white light indication respectively.

LDR is mounded in a tube, behind the lens, and is intended for the object. Colored glass filter should remain in front of the LDR as shown in the picture. Make three kinds of it and fix them in an appropriate case. Adjustments are critical and the gadget performance would depend on the proper fabrication and use of correct filters and light conditions.