Building an LED board

I am trying to build a custom LED board using 18 5630 LEDs.
So far I've been using a strip light that I cut into 6 3-LEDs pieces which I then soldered back into the shape that I need and it's working fine, but it's not an optimal solution.
So now I was looking at replicating the circuitry by connecting every 3 LEDs in series with a 220 ohm resistor, then connecting each 3-LEDs unit in parallel.

I've contacted a few people who build custom boards and they are giving me hard time saying thinks like "it won't perform well" or "it will be flickering", very vague, and at the same time wanting to build a driver on the board which results in a more expensive board, or build a very simple constant-current powered board.

Efficiency aside, why wouldn't it work? I see LED strips and simple LED modules installed everywhere that use a simple resistor to regulate current.

Any insight?

I see no reason why a bunch of series-connected LED's running in parallel with resistors to prevent current runaway would be an issue. So long as your battery supplies the voltage required by the series emitters and will be able to handle the current load from the parallel branches you should be fine.

What is your power source?

How many of these boards do you want?

Semiman

SemiMan said:

What is your power source?

How many of these boards do you want?

Semiman

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The power source would be a power supply, you know one of those Constant Voltage drivers (power supply), I'll need at least 25 maybe 50, more in the future.

Are you a manufacturer?

So let me get this straight: you want a single board, with 18 Philips Luxeon 5630 LEDs, in six strings of 3, each string with a current limit resistor, to be powered by a regulated 12V plug-in power supply?

As an engineer who does this kind of thing for both fun and money, I can definitively say there's no reason this can't work perfectly well. Certainly there are specific ideas or implementations that might give trouble, but based on what you have posted, those can be easily avoided. Anyone who tells you otherwise is either blowing smoke up your a**, or doesn't know what they're talking about, or possibly thinks you want something different that what I think you want.

Those quantities are kind of low for professional design houses, unless you have pretty deep pockets. If you came into my employer's shop, you probably wouldn't walk away with a custom design and 50 boards for under $2000, probably more.

It sounds like you might be pretty handy; if so you could (with a little help from your friends) design and build your own boards for a fraction of that cost. There is free design software available, and some board houses where you can get boards stupid cheap. For this design with fairly few parts, some of the big-name software packages have free demo modes that would work too.

Is there some reason you want to use so many LEDs? It's possible to get more light and as good or better CRI in a single LED, for less (I think) money.

Depending on what you are using this for, you could go FR4 not metal core. FR4 is cheap and likely would work, but those super cheap boards are rarely with white solder masks, etc.

The more details you can provide the more help we can provide.

Semiman

You can now get white. $10 surcharge, per order. This is a recent change at the house I use.

DIWdiver said:

So let me get this straight: you want a single board, with 18 Philips Luxeon 5630 LEDs, in six strings of 3, each string with a current limit resistor, to be powered by a regulated 12V plug-in power supply?

As an engineer who does this kind of thing for both fun and money, I can definitively say there's no reason this can't work perfectly well. Certainly there are specific ideas or implementations that might give trouble, but based on what you have posted, those can be easily avoided. Anyone who tells you otherwise is either blowing smoke up your a**, or doesn't know what they're talking about, or possibly thinks you want something different that what I think you want.

Those quantities are kind of low for professional design houses, unless you have pretty deep pockets. If you came into my employer's shop, you probably wouldn't walk away with a custom design and 50 boards for under $2000, probably more.

It sounds like you might be pretty handy; if so you could (with a little help from your friends) design and build your own boards for a fraction of that cost. There is free design software available, and some board houses where you can get boards stupid cheap. For this design with fairly few parts, some of the big-name software packages have free demo modes that would work too.

Is there some reason you want to use so many LEDs? It's possible to get more light and as good or better CRI in a single LED, for less (I think) money.

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WOW, thank you for the feedback, and the help. Let's see:

• YES to the 12V power supply, probably hard-wired
• I am doing this for fun, but I could end up selling it to a few friends and family, and possibly do a kickstarter
• I am pretty handy, I've used soldering iron before, but never on such a small small small scale as LEDs, but I am willing to invest a few dollars and a few days to learn my way: could you link the "free design software", the "board houses where you can get boards stupid cheap", and the "big-name software packages have free demo modes"; or already written posts/articles.

The reason why I am leaning towards populating the board with so many LEDs is to have a uniform glow across the entire surface of the board, like a small shallow sign.

Stupid cheap boards: www.seeedstudio.com, go to the Services tab and look for fusion PCB. These are 1/5th to 1/10th the price of most other board makers. There are a couple others that are similar, but I haven't used them.

Any soldering iron with controlled temp and a wedge tip should work for these parts. There are no spacing issues, so they should be easy for a novice solderer. You want 650-700 deg F. Flea-bay is a good source (that's where I got mine, a very nice used iron for under $100). Haaco, Weller, Pace, and OKI/Metcal are good names for both new and used equipment, no-name new is cheap and probably okay for low-volume stuff. Make sure you get or can get a new wedge (aka screwdriver) tip, 0.50" to 1/8" wide. A bad tip can make a good iron work like crap.


Free software:

Several board makers offer free design software. Advanced Circuits (aka 4pcb) and PCBexpress are two that are very good, but they require you to order boards from them and they are not cheap. I use AC for most of my professional proto boards because they are reliable and reasonably priced, they make high-quality boards with fairly quick turn-around, and I have gotten to know them well. They offer a free check of your layout to see if there are obvious errors, and you don't have to order from them to get that service, which is totally automated. And once you order, an actual person looks at your design before making it. Several other vendors offer similar service, but I've never used anything but AC.


Free software with no strings attached:

Going to a board maker and using their free software often ties you to using their board services as well, and most of them aren't cheap. Using truly free software allows you to choose your board maker. Eagle PCB and PADS are two that I know offer freeware versions, but there are many others. I would look for something that installs easily on your machine and allows you to make gerber files.

I agree with seeed and Eagle. Eagle has a bit of a learning curve, but it's pro-grade software with only a couple of restrictions on the free version (two layer boards, size restriction). Actually, even the size restriction can kinda be worked around with the latest version of gerbv (viewer of gerber files), allows you to merge multiple boards into one (goof for panelisation, too). Oh, gerber seems to be the most used file format, every board manufacturer should be able to handle gerbers.

Depending on how much free time you have, expect to spend a few months at least in learning and development.

As a side note for anyone after a temp-controlled soldering iron, check out HobbyKing, they have a ridiculously cheap good quality soldering station, if it's ever in stock; think $15 or so. Under tools / hand tools. Even got dedicated plug/voltage versions to suit your area.

That's great info, I will be playing over the weekend and I am sure I will have more questions on Monday.

Thank you DIWdiver and RoGuE_StreaK

That soldering station from Hobby King has a thin conical tip that is only okay for soldering fine, small parts. It might do for this board, but probably not for the rest of the job. You'll want some beefier tips if you are soldering anything bigger than 22 ga wire.

Fortunately, this iron is a knock-off of a Haako 936, and you can get tips many different places, including fleabay. Make sure you get the right size though, Haako made three different grip sizes, and each one has a specific tip size.

The 936 knock-offs seem to be disappearing in favor of the 937 knock-offs. I don't really know, but I suspect the main difference is an improved tip design. You can get a 937 for $30, and a dozen assorted tips for $13, both with free delivery. It's more money, but it's a lot more iron.

Now, off to see if I can get my board files ready for Seeedstudio...

$15 HK hakko clone is great; get some (real or fake) chisel tips from ebay or something. 1.6mm width at the tip is a good size generally.

Thanks for the "tips" guys (pun not originally intended), didn't realise it was a 936 clone, any thoughts on whether this 1.6mm chisel tip will fit the HK?
Any other useful tip sizes/shapes for certain jobs? (sorry, hijacking thread)

[EDIT] Didn't really pay attention to the model; says on it "Yihua" (or something like that) 936, mighta been nice to get it as the "Atten" version, which is the clone brand of my hot air rework station.

RoGuE_StreaK said:

Thanks for the "tips" guys (pun not originally intended), didn't realise it was a 936 clone, any thoughts on whether this 1.6mm chisel tip will fit the HK?
Any other useful tip sizes/shapes for certain jobs? (sorry, hijacking thread)

[EDIT] Didn't really pay attention to the model; says on it "Yihua" (or something like that) 936, mighta been nice to get it as the "Atten" version, which is the clone brand of my hot air rework station.

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Was working on a contract and had a good power supply blow up. Desperately needed something with 5amps and 30v and found a guy selling these Yahua supplies locally on Kijiji. It was Sat night so options severely limited. Bought the two I needed I think $125 each. Did what I needed but the worst pieces of crap you can imagine. In a week the display readings were off. Ripple was high under load, and the terminals were the cheapest crap I have ever seen.

My advice is to spend more. I have had my weller station for 10+ years and as good as new. Like a good multineter you will not regret it.

Semiman

I agree with DIWdiver, nothing wrong with what you are trying to do.
As a trail, you can purchase "vero-board" also known as stripboard. Easy to work with and great fun to make.