The Planted Tank Forum - View Single Post - A Cheap, Simple, Compact DIY LED Controller/Driver COMBO.
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post #29 of (permalink) Old 02-26-2013, 05:59 PM Thread Starter
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Join Date: Jan 2010
Location: "Out West, in the Land of Fruits & Nuts"
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Originally Posted by All your base View Post
Now, slap an I2C PWM chip on those boards instead of running directly off a PWM pin from the AVR and you've got enough bandwidth to add tons of channels! I doubt most hobbyists need that though so it would be a bit wasteful...

What were the failures on the integrated unit if you don't mind sharing? I'm curious to know if they line up with what I've seen over time. I stopped using the CAT4101 because it bakes itself so easily. I felt like I was spending more time testing and replacing CAT4101 drivers than playing with new projects, which was frustrating to say the least. So far I've not had any failures on LM3409s though I really don't like soldering something that fine. I'm thinking my next version might use the PDIP package.
I'd really like to expand on the original "Typhon's" capabilities, but alas - I suck at the programming side of these projects! I've had plenty of training with electronics, per se, but I'm too "visually oriented" when it comes to learning something abstract like writing code.LOL I spent my youth working as an automotive tech and specialized in Automotive Computer Control diagnostics, so this low voltage DC stuff is easy for me to understand. It's the software that has me baffled. Sure- I can "hunt & peck" and cobble something together from existing code, but I'm completely lost otherwise.
It's kinda funny- My current Led lighting system still runs off 15 Cat4101's that I installed right after they were introduced on the "DIY Led driver" thread over on ReefCentral. They're maxed out at 1,000ma and I haven't had a single failure yet. Heck- my cat's are still on PcB's that I etched by hand, since I hadn't learned EAGLE yet.LOL
Maybe the difference in experiences with the CAT4101 has to do with cooling? Mine are bolted down directly to the same heat sink as my leds, so they never get too hot. I always try to maintain cooling for the Cat's at "overkill" proportions. I even go so far as to add large fan cooled heat sinks (originally designed for cooling VGA's) to my Cat PcB's, especially if they're being used by someone who's not familiar with balancing their power supply's input voltage vs. their led string Vf and the required .5-.8 volt "headroom" for the Cats.
Here's a picture of my "SmartyCat"PcB.( It works well,(as long as you're careful with it)

The Pcb design-

The backside (VGA Heat sink)

I'm now used to soldering the LM3409, as I've built at least 100 drivers that use them. I've found that, most of the time, there's already enough solder in the solder mask to do the job without adding any more. I add a liberal amount of flux to the PcB prior to heating the LM3409's pins and pads, and Viola! all pins are soldered with no "solder bridges".

225 Gal, Glass "Reef Ready" w/ twin Iwaki Pumps & 2 Ocean Clear inline filters.Lighting- Custom built DIY 600 watt LED system, BlueFish "mini" Led Controller,iAqua Aquarium Controller , and a 20lb CO2 system w/ Milwaukee Ph Controller.
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