keep the level of light with LDR

[lonkenzo]

Hello,
i would like to get a circuit wich use an LDR to provide the level of light in a room. My problem is that generally an LDR is use to get a binary information( light on or off).
I want each time to know what is the information about the light level stored in a voltage or a current.
Thank you

 

[kak111]

I hope you find your idea here............

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http://fetweb.ju.edu.jo/staff/Mechatronics/LShareef/MandI_files/Case Studies/1 light luxmeter.pdf

 

[betwixt]

LDRs are analog devices, their resistance is proportional to the amount of light falling on them. They can be used to produce binary levels but only in some opto-isolator applications or where they are followed by a comparator circuit.

I have even used them to maintain constant light levels in a design that automatically opened and closed horizontal window blinds.

The get a voltage or current measurement, connect the LDR in a bridge configuration or as a potential divider with other resistances being fixed values. You can then scale the voltage with an amplifier and measure it with a meter or an ADC.

Brian.