Chuck's Planted Aquarium Pages
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A Night-light for my aquarium!No, my fish aren't afraid of the dark (at least they've never told me so). Long ago, I learned to enjoy sitting by my tanks with small flashlight late late at night, in almost total darkness, watching the night-life in the tank. But a flashlight seems to scare the fish. They definitely notice when it flashes by them. So I sought out a more effective and less intrusive night-light for my tanks. I first tried to wire a couple of those cool new nightlights they sell at wal-mart, etc. Those cool "Indiglo" flat panel nightlights. Seemed like a good match. But I found they don't put out enough light, and possibly a bigger drawback: They require 110AC, which isn't something it's fun to tinker with, especially around water. Plus, I found that they can't take the humidity. They fail rather quickly exposed to high moisture levels. I've finally found a "perfect" solution. It uses a small plug-in transformer (12v DC), and 16 LEDs. It took some trial, but I found some VERY bright red LEDs, and some VERY bright BLUE!!! LEDs. Blue LEDs were news to me, but they are really cool. I got some from a surplus place. All the LEDs, and the plug-in transformer cost under $20.00. I wired them up, and attached them to the hood of my tank. I leave them running all the time (barely any power usage, no heat, etc.) The light they produce is enough to view the fish with, once my eyes adjust to the darkness of the room. At that point, it looks just like moonlight shining down thru the water. I wired the LEDs in four groups of four. They are spaced across the 4' width of my 75g tank, and provide pretty even lighting. I've noticed that because they are located at the front of the tank, everything looks very FLAT. I intend to wire another set of LED boards, and attach them over the back of the tank. Here are some pics:  The front part of the hood opened up, with the lighting assembly visible (pointing up in this pic, the LEDs point straight down once the hood is closed.)
Building these nightlights requires some soldering ability, but nothing fancy. I obtained the main parts from a great electronics surplus dealer 'The Electronic Goldmine', http://www.goldmine-elec.com
Their online catalog is horrible, and it's almost impossible to find what you are looking for. But their printed catalog is nice, free, and great fun for anyone interested in electronics and tinkering. Parts List The following items were obtained from Electronics Goldmine:
Normal LEDs (reds, most yellows, and most greens) operate on 1.5 to 2.0 volts. The blue LEDs don't even light up until the voltage gets to 3.0 volts, and they seem to operate very brightly with 4.0 volts, yet they stay cool, so I don't think 4.0 volts is too much for them. I've pushed them as high as 5 volts, but they were very warm, and would probably fry after a few hours.
 Click for larger diagram in a new window As shown in this diagram, I wired 8 red LEDs in series. That means that each red LED got 2vDC. I also two strings of 4 blue LEDs in series, so that each blue LED got 4vDC. NOTE: My electronics guru brother (Hi Chris!) slapped me around and made me realize that I've forgotten much of my basic electronics training. He wrote: "Remember Kirchoff's Law? Voltage is equal in all branches of a parallel circuit, current is equal on all points in a series circuit." Of course my brother and Kirchoff are correct. So, the diagram has been simplified, and now it only needs two wires running the length of the tank. In addition to making the wiring cleaner, this will also serve to protect the LEDs in the event one of the LEDs fails for some reason. In case you aren't familiar with electronics, I'll warn you that LEDs must be wired in the correct direction. If you look carefully at the inside of an LED, you can see where the two leads end, and almost touch each other. One side is larger, and has a flat horizontal section. That flat portion is sometimes referred to as an "anvil", and is the negative side. The other side is just a straight post. The straight post is the positive side.
 If you look at the photo of the circuit board, you can see the layout I used. It's pretty simple. The seperate wire in the photo that isn't connected in the picture is the negative wire. It runs from the last circuit board back to the power supply negative wire. I hope this provides enough information. Let me know if I left anything out. Also, if you are totally new to electronics, email me and I can try to talk you thru this. It's really not a tough project.
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