Light sensors

[Bush]

Hi, I want to make a simple circuit to power an LED. I want the led to turn on when a light sensor detects the absence of light. I'm wondering if anyone knows of a small light sensor I could use for this, one similar to those found in night lights. Thanks!

 

[Hermaphroditus]

http://www.homedepot.com/webapp/wcs/sto ... rketID=249

Would this work?

 

[XCVG]

You need a photocell and I think a transistor to invert the signal. I should be able to get a schematic sometime today.

 

[mymixed]

There are three things that can do this for you. One is called a Photoresistor another is called a photodiode and the other is called a phototransistor. Photodiodes and Phototransistors simply turn on and off. Photoresists can calculate resistance (hence it's name) So depending on the certain amount of light going through, that is how much voltage will be let through. So which kind do you want?

- mymixed

 

[XCVG]