This follows on from the Potentiometer’s example.


Light Dependent Resistor

To build this circuit, push the LDR into the breadboard with one leg connecting to A7 and the other to the ground rail. Plug a 10k resistor from the 5v power rail to the same analog pin, A7.

A LDR or Light Dependent Resistor varies its resistance depending on the amount of light shining on it. This variance changes the voltage we read on the analog pin.



Did you notice on this line ldrValue = map(ldrValue , 0, 1023, 255, 0); we reversed the 0 and 255? This means that the lower the voltage read (less light) the higher we make the value we write to the LED, making it brighter.

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