LDR detector

Hi
I want explain my project in brief . please help me about make it .

I want to have a LDR detector with variable range of light . let me
explain more I connect a LDR to a LM2903 comparator and I want detect
output in any condition ( in brightness and darkness ) but it not
possible . I am amateur in electronic and I don't know what is wrong
Please offer me a circuit for solve it .
Thanks

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