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Old 05-04-2011, 07:58 PM   #1
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Default DIY PCB's for DIY LED Systems.

I’ve been keeping “high-tech” planted tanks since 1994.Ever since I started keeping them, I’ve been tempted to try every new piece of technology that came out to make growing aquatic plants easier( special nutrient enriched substrates, water conditioners, automated Co2 injection systems, ect..) and more economical. Lighting the tank economically has always been problematic, for a number of reasons, up until now. I started out with Metal Halide and found that it could grow plants very well, but the associated cost of replacement bulbs, the intense heat they produce, and the amount of electricity consumed was costing me a small fortune. I replaced the Metal halides with power compacts as soon as they were available. My most recent system consisted of (6) 130 watt PC bulbs for a total of 780 watts. They performed well enough to grow plants, ran cooler than Metal Halide, but still had heat and replacement costs that I deemed too high. I started to research into the possibility of replacing them with high power leds not long after they were first introduced to the general lighting market. LED technology has advanced at a rapid pace over just the last few years, so I decided to try my hand at utilizing them for planted tanks. I’d seen a few of the newest led fixtures to hit the market, and was blown away at their high cost. Because of this, I decided to go the DIY route and build my own design to save some money.
My first build would be for my 225 gallon tank. This tank houses mostly small tetras, shrimp, corydoras, ect.. The plants are Java fern/Anubias Barteri growing on driftwood and glossostigma on the substrate. I knew the glosso would need high light levels to encourage it to spread, so my design utilized 90 Cree XRE- Q5 leds driven by 15 Onsemi CAT4101 driver IC’s mounted to homemade PCB’s powered by 3 meanwell 24Vdc 6.5 amp power supplies. I divided the leds into 3 groups of 30 and mounted each group to heatsinks sourced from old Sony Car amplifiers. More info on My first led system can be seen here -

Here’s a photo of my tank from a few months ago- the Java fern/ Anubias Barteri have
grown considerably since then and the Glosso now completely covers the substrate.

As I mentioned before, the Led drivers that I used were constructed at home using MicroSoft Paint for the PCB design and etched in my kitchen. This DIY route worked well until my designs became complicated enough that these methods were no longer feasible. I have since learned how to use a free software that allows me to design nearly any PCB that I need and have it manufactured and delivered in as little time as a week.

These are some of the PCB’s that I’ve had created so far. This one will drive 2 strings of 6 leds.

This one will dive 4 strings of 6 leds. Both designs include 5 volt regulators for powering the IC drivers from a 24vdc power source and Pulse Width Modulated Dimming circuits.

Here’s the 4 channel model fully assembled and coated with non- conformal coating for protection from the elements.It is also contains a 12 volt regulator and is mounted to a small fan cooled heatsink.

The free software that I use is called Eagle and is available as a freeware version here -
I learned how to use the software with an online tutorial here-

And I use Seeedstudio to manufacture the PCB designs. Their services are available here-

The whole process begins with the Eagle software, once you learn how to use it. You start by creating an electrical schematic using the software’s libraries to choose the electrical properties ( voltages, resistance, package style, ect..) for the components that you want to use. You then draw all the wiring connections between the components and run the software’s Electronic rule check feature to check for faults. When the circuit/ schematic is finished up and you’re happy with your work, the software can be asked to convert your schematic into a board.
The board show begins as a clean slate with all your components off to the left side of the screen. Your job is to use the move command to arrange every component to where you want it placed on the board. Once that is done, you can route the various connections manually or use the “auto-route” command to let the software do it for you. The software has a “design rule check” that can be run to verify if the board design is good enough for a Board house to manufacture. Each Board manufacturer normally provides their own “design rule” software file that can be loaded into the Eagle program for the needed checks.
.When you’re happy with your board design, the Eagle software can be used to convert the board into Gerber files using it’s CAM processor. Gerber files are used by the board house to program their machinery for the actual board production run. Each Board house will furnish you a CAM file that can be loaded into the Eagle software and provide the correct gerber files needed for their particular tooling.

Here’s an actual PCB design that I sent out for production this week.

That’s about all the info that I can share so far. If anyone has more questions just ask.


Last edited by O2surplus; 05-04-2011 at 10:21 PM.. Reason: photos not loading
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