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O2surplus 05-04-2011 07:58 PM

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 - http://www.monsterfishkeepers.com/fo...ht=leds&page=2.

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.
http://i861.photobucket.com/albums/a...h_IMG_1068.jpg


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.
http://i861.photobucket.com/albums/a...h_IMG_1166.jpg

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.
http://i861.photobucket.com/albums/a...h_IMG_1165.jpg

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.

http://i861.photobucket.com/albums/a...h_IMG_1169.jpg



The free software that I use is called Eagle and is available as a freeware version here - http://cadsoftusa.com/freeware.htm
I learned how to use the software with an online tutorial here- http://www.instructables.com/id/Turn...ic-into-a-PCB/



And I use Seeedstudio to manufacture the PCB designs. Their services are available here- http://www.seeedstudio.com/depot/fus...78236b78f5b780

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.

http://i861.photobucket.com/albums/a...uadcat4101.png

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

O2Surplus.

evilc66 05-04-2011 08:22 PM

Might want to actually upload your images ;)

larams67 05-04-2011 09:20 PM

There is also expresspcb if Eagle is to complex.

If anyone has a laser printer they could print out there design in reverse and then use a clothes iron to transfer to some copper clad. Etch it and drill it and you've got a custom pcb. I've made tons of tiny intricate buffer circuits for amplifiers this way with very small traces. Works great if you just need one or two boards.

O2surplus 05-04-2011 10:14 PM

Quote:

Originally Posted by evilc66 (Post 1378773)
Might want to actually upload your images ;)

It seems photobucket is not my friend today, looks like I'll just have to post them as thumbnails:hihi:

intermediate_noob 05-06-2011 02:45 AM

I followed your threads on Monsterfishkeepers and have really been interested in doing a similar project on a smaller scale. There are some people over at nanoreef that have put up a few of the single Cat4101 driver boards that I thought I might use to just drive one or two strings.

My question for you would, is this really worth it or would it just be easier to go with a Meanwell or something similar?

Thanks a lot for posting, this is such an awesome DIY.

evilc66 05-06-2011 02:36 PM

Depends on what you enjoy doing. Learning a new skill like pcb design is a challenge, but a fun one. The CAT4101 drivers are easy to use, and certainly cheap enough to consider. The only drawback is that they are a linear driver, which means that the excess voltage difference between the LED forward voltage and the source voltage gets burned off in heat through the driver chip. To minimize this, you have to keep the delta between the two as small as possible. This typically means either careful planning of your LEDs for a fixed output power supply, or you get a power supply that can be adjusted slightly to minimize heat related issues.

madhatter4 05-06-2011 03:45 PM

Quote:

Originally Posted by larams67 (Post 1378826)
There is also expresspcb if Eagle is to complex.

If anyone has a laser printer they could print out there design in reverse and then use a clothes iron to transfer to some copper clad. Etch it and drill it and you've got a custom pcb. I've made tons of tiny intricate buffer circuits for amplifiers this way with very small traces. Works great if you just need one or two boards.


Even easier then the clothes iron is a laminator. Some modes require very little modification to accept a pcb. They provide much better heat and pressure distribution.

intermediate_noob 05-06-2011 03:49 PM

Quote:

Originally Posted by evilc66 (Post 1380603)
Depends on what you enjoy doing. Learning a new skill like pcb design is a challenge, but a fun one. The CAT4101 drivers are easy to use, and certainly cheap enough to consider. The only drawback is that they are a linear driver, which means that the excess voltage difference between the LED forward voltage and the source voltage gets burned off in heat through the driver chip. To minimize this, you have to keep the delta between the two as small as possible. This typically means either careful planning of your LEDs for a fixed output power supply, or you get a power supply that can be adjusted slightly to minimize heat related issues.

Thanks EvilC, I have been reading your threads and others on the salt water forums and would really like to get into the DIY aspect of this so I think my mind is made up.

My thoughts were to start small and build a single driver board to light smaller thanks and then graduate up to a larger setup. Again, thanks for the reply and the information.

O2surplus 05-06-2011 05:12 PM

I used the Cat4101 driver in my set up for a few important reasons. They're cheap(about $3 ), require only a small amount of additional components, they accept a 5 volt pwm dimming signal directly from an Arduino( a meanwell needs 10v ),and they can be made to dim down to 1%,(meanwell's won't dim below 20%)
I also like the fact that with proper planning, you can save money by only having to purchase 1 power supply for your set up, instead of paying for another supply with every meanwell-(not to mention the problem of resonance between multiple supplies on 1 power circuit).

Neya 05-06-2011 06:55 PM

Quote:

Originally Posted by intermediate_noob (Post 1380302)
My question for you would, is this really worth it or would it just be easier to go with a Meanwell or something similar?

Thanks a lot for posting, this is such an awesome DIY.

Ive looked into this somewhat. It's worth it if you have a lot of LEDs to drive OR you can build the pcb yourself.
Otherwise (especially if youre having some place make/send it) not really, it'll be a lot less involved in time and funds for 1-2 pcbs.

O2surplus 05-06-2011 09:06 PM

Quote:

Originally Posted by Neya (Post 1380837)
Ive looked into this somewhat. It's worth it if you have a lot of LEDs to drive OR you can build the pcb yourself.
Otherwise (especially if youre having some place make/send it) not really, it'll be a lot less involved in time and funds for 1-2 pcbs.


You are right. "Economy of Scale" will not work for smaller led builds, especially, if you have unneeded boards leftover, that you're unable to sell. But the costs of having them made by a board shop vs. purchasing all the needed parts( copper clad boards, etch-ant,tin-plate,tools, ect..) gets pretty close, without the mess.

wootlaws 05-08-2011 08:36 AM

thanks so much for sharing this. at this point of leds the only drivers that seem most popular and easiest to deal with are meanwells. let's say i plan to have 100 leds, i would need at least 10 meanwell drivers which would be almost $300 at $30 each. as you had already stated having 10 of these drivers in 1 ac outlet doesn't seem that feasible. currently i am trying to find a way to power my 100 leds.

O2surplus 05-09-2011 12:27 AM

Quote:

Originally Posted by wootlaws (Post 1382261)
thanks so much for sharing this. at this point of leds the only drivers that seem most popular and easiest to deal with are meanwells. let's say i plan to have 100 leds, i would need at least 10 meanwell drivers which would be almost $300 at $30 each. as you had already stated having 10 of these drivers in 1 ac outlet doesn't seem that feasible. currently i am trying to find a way to power my 100 leds.


The Meanwells will run 12-14 leds per driver depending on the led's Vf.
The Cat4101 chip will run 6-7 led's per string depending on the led's Vf.

You would need at least 8 meanwells to run 96 leds or 16 cat4101's and an appropriately rated 24 volt power supply. The amp capacity of your power supply will be determined by multiplying your desired drive current by the number of Led strings. For example- 16 strings driven @ 700 ma would require 11.2 amps. A Meanwell 24v-13amp power supply would work perfectly, and can be found dirt cheap on EBay.:D

evilc66 05-09-2011 07:58 PM

Quote:

Originally Posted by O2surplus (Post 1380759)
I also like the fact that with proper planning, you can save money by only having to purchase 1 power supply for your set up, instead of paying for another supply with every meanwell-(not to mention the problem of resonance between multiple supplies on 1 power circuit).

There are alternatives to the Meanwells that solve almost all the issues the Meanwells have. The Thomas Research drivers are far more efficient, higher PFC (less surging/resonance), run cooler, don't require a power supply for dimming, and have higher voltage and current models than Meanwell offers. The 20% minimum dimming is still an issue, but that will be true for any buck topology driver with a wide range of LED capacity. That's all down to inductor sizing.


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