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LDR or Light Sensor

Last post 05-12-2008 8:33 PM by andy.harris. 2 replies.
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  • 04-25-2008 4:15 PM

    LDR or Light Sensor

    Hi all

    Could anyone tell me how to wire an LDR to the brick using an anologue input to give a reading, I would gather you put 10v through it and what comes out the other side will go into anologue in.

     

    Any Ideas

     

    Experementation.team 

  • 04-25-2008 4:40 PM In reply to

    Re: LDR or Light Sensor

    Connect LDR in series with a resistor, look at datasheet for resistance range of the LDR and pick something in the middle for the fixed resistor. Then connect one end of LDR to 5V, the center connection to the analogue input and the resistor to ground.

    What you have is a potential divider, the voltage at the input will vary dependant on lighting levels.

    What LDR do you have.

    There are also light to voltage devices, that are similar to IR receivers, 3 wires.

    http://uk.farnell.com/1182349/optoelectronics/product.us0?sku=TAOS-TSL260R-LF

     

  • 05-12-2008 8:33 PM In reply to

    Re: LDR or Light Sensor

     Alex

    Ahh, me thinks we need to know the bigger picture of what you want to achieve -- if its a twilights thing then we have much neater ways of doing this.  If it is for monitoring the state of a light (for example in a loft) then the post above is what you need.

     Regards

    Andy

     

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