moonlight cycle schematic

Jerry, how does the LED light or get dim? I thought they had to have a certain amount of juice or they simply won't come on at all.
 
if you make a sawtooth wave you can adjust the voltage that goes to the LED, LED's do change intensity with voltage (try dropping a resistor across one and you will see the light change)
 
Jerry, it might be easier to change the 100K resistor to a 0-470K variable.
I haven't punched in the numbers yet to see what period the current setup gives you But if what you're using currently is within an Hour, you would need to change the cap to almost a farad (use a supercap). I think I'd still opt for a Potentiometer so you can fine tune the unit then seal it with nail polish
 
Sweet! And here I was proud of the scheme I came up with and have been using for quite some time...

I've got 2 13w PC Actinics, one mounted on the left of the hood, one on the right. Everything on my tank is controlled by X10 run by a Cron on a Linux box. The first 7 days of a month, the left one runs at night, the 8th-14th of the month they both run at night, the 14th-21st only the right one runs, and the 22nd through whatever's left none of them run...
 
Russ is right... a supercap will be needed. If you multiply multiply the 22uF times the 47K just below it... you get an approximate time to charge the cap. Problem is that supercaps have a lot of leakage and the capacitance tolerance is large. A potentiometer would help to tune it, but again... depending on the capacitor, the current may be so small it won't charge as fast as it leaks. Remember we are talking about 28 day cycle, this would much better much shorter cycle.

If I had the time to play with it... I'd try it myself. Based on my experience and resources that's the kind of answers I'm getting.
 
I have three of the led lights and the controller from fish bowl I bought back when I was first getting setup.

I am happy with these and they seem to be fine in quality of contruction.
 
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