Anyone come across a light that can...

Switch on and off when it goes dark, after all i see people buy Timer Switches all the time and why? because they can make the light come on when it's dark and off when it's not dark, but problem with timers are, as the days and weeks pass, it's no longer dark at 7pm but 6:45pm and every few weeks you have to change it...

Well what i've not yet seen is a photovoltic cell that simply turns your home / house lights on and off, Lamp Stands, or your main lights.. what i was thinking was a small cell on the roof to turn the main lights on and a cell in the house to turn a small lamp on..

that way, Burgalars who watch the empty house will see that the lights don't come on at exactly 6:33pm every day but instead 6:30pm or 5:40pm if it's really cloudy and or raining....

Maybe even replace the on/off switch with a photovoltic (whatever they're called, i'm calling them that because i think it's called that lol) so above the on off switch is the sensor, which turns on the lights when it gets dark in that room.

or a block you plug your lamp stand in to which plugs into the wall which simply turns it on / off...

If they do exist, tell me where to get one from if they don't how hard could it be to make one?

These are readily available for security lights. There is a large selection in just about any big box hardware store. Here's a simple one from Lowes:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=10755-290-SL4000&lpage=none
They can be wired in place of the existing switch or between the switch and the light.

There is also a model that screws into a light bulb socket:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=72657-207-SLC-4CG&lpage=none

You can get them in almost any DIY or hardware store. Built into the light socket, light switch, even the bulb itself.

cool, thanks