Hi all,

I am looking into the possibility of using a photo resistor or similar that can be scaled to ##### digits like a lux meter. If a light within a room stops working I need it to be acurate enough to be able to sense the lowered value. I am asuming a normal photo resistor wont be accurate enough?

Thanks

 

Hello,

The chapters of this eBook might get you on the way:
http://www.intl-lighttech.com/applications/light-measurement-apps/light-measurement-handbook/

Bertus

 

Someone has told me this should do the trick..

http://www.taosinc.com/ProductDetails.aspx?id=32

http://uk.farnell.com/taos/tsl235r-lf/photodiode-sensor-l-volts/dp/1182352?Ntt=TSL235R-LF

I think it can be scaled so its maximum is set to say 1000. Then in real terms if the rooms lights when all on causes it to read say 500 the the user will be aware with all the lights on they should get a value of around 500. If one of the lights were to fail and the reading dropped to say 300 then the user would be aware something is up?

It is going on a GSM controller i.e the user sends the text message "light" and it returns with a value...if the value is lower than expected then they will know a light is not working.

I am trying to define how sensitive these components are rather than just on/off