A PCB for LED arrays

[Tom in NH]

I'm looking for a printed circuit board that will let me hook up at least 40 leds for a household lighting project. Has anyone ever seen something like this for sale?

--Tom

[ron t]

Would you be open to the idea of etching and drilling your own board?  That would

allow you to design it, the size & layout, to suit your application.

[wildbill hickup]

Hey Tom,

Haven't seen any that didn't allready have the LED's in them, but I have an idea that might work. If you got pin connectors (like the ones they use on harddrive/diskdrive cables) female that solder onto PC boards that would give you several possisions to hook LED's to. Are all 40 going to be in the same place or are you running then to different locations??

 Bill

[RatOmeter]

Not seen'm pre-made, myself.  You could your own like I did, using a perfboard from radio trash.  

The one shown below is a CD-ROM drive converted to an LED toy for my young'ns

I've also made one with (oddly enough) 40 LEDs with the same material... and another that plugs into the parallel printer port of a PC under software control.

Fun, fun, fun.

[Matt]

Try  http://www.oatleyelectronics.com  They have many led kits, and led drivers for normal leds, and the hi brightness 1w, 3w, and 5w luxon leds etc.

They  have this kit which has 30 leds.

http://www.oatleyelectronics.com/kits/k202.html

[richhagen]

I noticed the number 40 Led's, if you are planning to hook 40 in series and power it off of rectified houshold current, I have a word of caution.  I tried this a while back and it didn't work out so well.  Diodes short by failing, and thus with the first failure, the current and the voltage drop across the surviving diodes causes them to fail.  If this is what you have in mind, I would recommend converting to 12 volt DC through a switching supply if possible, or a transformer and connecting three in series through a resistor to limit the current to under the rating for the LED's, probably a 120 ohm or so for the common 5mm type.  This is safer, and if one string fails, your only out 3 LED's.  Also, keep in mind that LED lighting in its current state is still much less efficient than flourescent lighting, see the lighting link off the other power home page.  Rich Hagen

[debequechute]

Here's one that's just the board, holds 72 LEDs for $10.

http://www.bgmicro.com/prodinfo.asp?prodid=LED1071

[ghurd]

I have a round board for 24 LEDs. Have a few similar rectangular ones also.

Set up for 8 groups of 3 LEDs (12v). A ring in the center with some holes for resistors, diodes, etc.  The OD is 2- 5/16, the same OD as a 2" PVC slip joint making for a little lathe work on plastic pipe fittings for a lot of mounting possibilities.

It is heavy duty double sided 2 oz plated copper, with the 'traces' being as large as possible. Almost inside out compared to most boards. Huge pads, tiny lines between them for maximum heat sink. No solder mask.

A little dremel tool work or a couple jumpers, and we have used them for 6 and 24v.

I have about $5 each in them. I could email a scan if you want.

Avoid too many in series, or there will be failures like Rich said.

G-

[whirlybird]

Hi Tom.

I think i may be able to help you with your lighting project.A recent article published here in australia contains all the data,diagrams and printed circut details to make a small round 40 led lamp.

It is very comprehensive.The kits will be available shortly or if you wish to contact me i can dcc you the file on MIRC

MIRC server name www//:alton-moore.net   port 6667 chanel name #otherpower or chanel name #vcats

Also atMIRC server www//:anotherpower.com port 6667 chanel name #otherpower

You will usually find the foot lurking on those sites.

PS, Any Ausies or kiwis interested in RE that care to contact me via MIRC we could put you on our local mail list we bulk buy some hard to get bits and swap info that is relavent to this side of the globe  

Hope this will be of some help.

Regards

thefoot

[wooferhound]

I used a breadboard. I plugged this all up and was using it in 10 minutes

I ran 120 volt power through a bridge rectifer with a 400mfd 200volt capaciter across it. The capaciter came from a trashed computer monitor. then I plugged three sets of 25 LEDs in series for a total of 75 LEDs. I found that I only needed a 10 ohm resister in series with each set of LEDs to get 20ma current draw. Then Plug and play...

[Tom in NH]

Thank you everyone for your very interesting ideas. You have given me a lot to ponder. I want something roundish, small and nice looking to fit in the 10 recessed lighting fixtures that are going in my new kitchen. I built a prototype that is pretty ugly, but it works and burns 6 watts. I'm powering them with 12vdc.  --Tom

[Jeff7]

I'll also suggest looking at per-hole-etched protoboards. Solder each LED just to the indivudual pads, snip the leads, except for about a quarter inch, and you can bend and solder that to the adjacent LEDs in series or parallel, whatever. Though series is better, since in parallel, there's a slight chance that one will start to hog the current, and blow itself out.