Req for help with variable-power date-adjusted LED light

[aprebyl]

Req for help

Thanks that is great

 

[Optikon]

Hi,

I'm not an electronics guru but I remember just a bit from my high-school class.

Project background: My wife is trying to breed a particularly finnicky (no pun intended) type of aquarium fish. Supposedly, these fish have behavioural patterns tied to lunar illumination. So, what I'd like to build for her is some sort of light that will provide low-level illumination that varies in intensity on a 30 day cycle. The idea is to simulate moonlight filtering through the water during the monthly waxing and waning of the moon.

My concept here is to use one or more LED's as the light source, but I'm looking for suggestions on two topics:

1) How do I get the thing to automatically adjust the voltage going to the LED's? I mean, how do I add a step in voltage every day for 30 days and then start over at 0?

2) Is there a way to get this whole thing to come on automatically when the main aquarium light (on a timer) turns itself off at the end of the day?

Any thoughts appreciated. Thanks!

#1) Use a PIC or something similar and a D/A converter. Both are cheap!
Your PIC controls the D/A and the output of the D/A goes to the LED. You can pic a D/A to give you many thousands of intensity levels. Of course you only need 30 settings. This is very easy to do.

#2) The answer is yes. You need one AC type relay powered from your timer. Use the appropriate set of contacts to switch power to your moonlight circuit.

 

[aprebyl]

cool thanks!

good idea!