The given circuit is tested by myself in NCE Robotics Club ( www.facebook.com/ncerobotics ) many times with various modifications, the given circuit works very effectively.
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| Figure: Verified circuit diagram of color detector |
The circuit can detect two different colors comparing the light reflecting capacity of those colors. As we know the light reflecting capacity of brighter color is higher than dark one, thus the different intensity of light reflected by different color surface will cause the different value of resistance in LDR ( Light Dependent Resistor ) sensor, which is converted into voltage levels by implementing LDR and a fixed resistor in voltage divider arrangement (but as fixed resistor we use preset to change the sensitivity as our desire and required level).
