linear light sesnor help

Using Arduino Sensors
1

Hi guys i hope you all doing well
am designing an automatic brightness control system , but am stuck on how would I figure out what type of linear light sensor should i use that could detect a high intensity of light coming from outside a room since my project is designed to be installed inside a room .Then the system can adjust the level of brightness inside the room based on the light coming from outside
any help or clarification will be appreciated

Thanks

2

Hi

Why dont u just use
1.
a photo diode, that u place at a point that should have a constant brightness,
and
2.
a comparator (either digital or analog), that tells the arduino if u need more or less artificial light?

i dont c

  1. why u need a linear sensor, or
  2. why u need to measure the sun/street light input...

Bye

3

Thanks for replaying
am using linear light sensor since the light intensity is not linear so I got to use to use a linear light sensor that linearized it . my project is a system to be installed inside a room then that system can adjust the brightness of the light in the room based on whats coming into the room from outside fx at 12 noon the lighs will be off and once it gets kinda darker like 4 pm where the sun is not really that strong then the light will be fx a 30 % brightness and once it gets really dark the lights will be completely off

and since the lights inside the room mainly depends on the light coming from outside the room I was thinking of some type of a light sensor that capable enough to detect the intensity of lights coming from outside the room . when i looked online for some light sensor i wasnt able to know what exactly will fit my project

any help please

4

what is bad about keeping the intensity constant at one point somewhere inside the room?
preferably a point that doesnt get direct sun light...

u could use a simple LDR and measure its resistance and keep that resistance constant by giving more or less extra light...
http://www.digikey.com/product-search/en/sensors-transducers/optical-photo-detectors-cds-photoconductive-cells-ambient-light/1967023?quantity=1&ColumnSort=1000011&fid=0

or an even cheaper photo diode (but i dont know what circuit u need for that):
http://www.digikey.com/product-search/en/sensors-transducers/optical-photo-detectors-photodiodes/1967048