Automatic, Biorhythm LED Aquarium Light

Step 6 All done!

In all, I'm very proud of the way this project went together. It took 10-15 hours in the end, mainly in experimenting and planning, but it paid off. Replacing the high-voltage driver and fluorescent tube with a small 12V power supply and efficient LEDs makes a huge difference in power consumption. I wish I had a kill-a-watt to test the before and after and give you absolute comparisons, but I know it's at least a good improvement. Not only that, I won't have to replace the bulb every 6 months when it burns out. While it's only a small improvement environmentally, it's better than nothing!

In addition, we never have to touch the light manually now. This gives us the assurance that the fish are setting their rhythms based on a regular light cycle, rather than the 'whenever we remember' phases, hopefully lengthening their lives. It also means we can go on vacation without having to worry about the fish light. Plenty of positives.

Possible Improvements
1) One thing I considered was adding a 'feeding light' to the outside of the light hood. This would light up when it was feeding time, and allow us to dismiss the light for that night with a button press. Since everyone in the family feeds the fish, it would keep us from feeding them too much.
2) I also considered adding an auto feeder into the mix. If I do that, I'll post a second instructable with the steps needed.

Conclusion
Though I've been a member since 2006, this is my first instructable so far. I hope to post many more as time goes on. Please give me feedback on things I didn't cover enough, as I'm always looking to improve!

Comments

[Hermeez]

How could this be adapted for a small saltwater aquarium. I think the LEDs need to have another spec.

[thewhite]

You have to remember that LED light is not suitable for most aquatic plants (don't bother if they are artificial ;-)), otherwise excellent job. (if you've got no plants, remember to change water on weekly basis about 20-30% a week. might be tap water) Also you can think about night light, 1-2h after main is switched off. For example 5 blue LEDs... Cheers.

[dreadnaught]

White led alone may not be suitable for plants. But what if you also added red and blue led's to match the Florescent lamp's spectrum?

[paryl]

Initially I would agree about the plants, but I'm honestly not sure... do you have more information? If you see the first comment and my reply... I haven't been able to find any information to say that LED light is any better/worse for the plants at all. I did find several LED "plant light" products though... so apparently they can be tuned to get the right balance. As to your second point, very true! In my case, when I brought the signal of the IRF510 to 0, it allowed a bit of bleed voltage (I don't know if mine is defective, or if that's expected and you have to negative bias it?) which gives a very faint glow. Simulates moonlight quite well.

[thewhite]

Hi, sorry for delay in answering. Output light from LED is monochrome, in some circumstances that is ok, (car light for example). For human eye there's no difference, for plants the difference is HUGE. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html here is basic article about photosynthesis, but you can find plenty of them on wikipedia or Internet.
Anyway, I haven't seen any serious planted tank setup with LED light.
Probably for some less demanding plants LED lights are fair enough, not for all definitely.

[blubrick]

It might be tempting to use tricolour LEDs to create a certain colour of light from the red, green and blue components, but that would be unwise because that is really only a simulation and will have huge ranges of the visible spectrum absent (possibly excluding critical wavelengths for plantlife). "White" LEDs, on the other hand, should be OK because they are not monochromatic at all. They are actually a blue or ultraviolet LED "chip" coated with a scintillant that glows in a fairly broad spectrum in almost exactly the same way as a fluorescent tube does. It's probably far from an an ideal solution, but white LED's should be pretty right.

[thewhite]

Actually I'm testing at the moment luxeon LED's as a source of light. They are 2 x 3W white (very small tank, rather jar than tank, without CO2 only easycarbo as a source of carbon). So far exactly as I expected, some demanding plants not growing as under normal T8/T5 light tubes. For other plants like java moss its ok, more or less the same growing ratio. I'm going to set up small tank/jar with glosstigma next week and see what happen.