Soldering a LED Display Matrix

So, I've learned the hard way that it isn't trivial to solder a LED
matrix. I've actually extended that lesson to realize any non-planar
graph adds difficulty to soldering.
Anyway. I was trying to build a 5x5 LED matrix (because I only have 25
LEDs right now, and it seemed like a good start).
I got two rows in, before I realized I wasn't going to be able to finish
it the way I was thinking. I was soldering all of the anodes together
for each row, and that was working fine, but then when I wanted to
connect the cathodes, I realized I hadn't left enough perforations to
solder enough jumpers and the LEDs. I also began to realize how much
work it was going to be to solder it all together. I'm fine with the
work, its good practice. What I'm wondering though, is am I doing it
wrong? Is there a better way to build your own display matrix? I know I
could buy them prebuilt, and I might do that for larger projects, but
this is a learning experience as much as a means-to-an-end.
On that same note, would it be generally cheaper to buy 8x8 led matrix
pre-made, or to build them myself? What about if I wanted RGB display?
Thanks for the feedback.
Reply to
Daniel Pitts
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Tim Wescott
Control system and signal processing consulting
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Reply to
Tim Wescott
Also
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Seeed Studio offers a very inexpensive board service. Double-sided, silkscreened, with solder mask for a as little as $1/board for 5cm x 5cm. The largest they do under this service is 20cm x 20cm (not quite 8" x 8", a pretty large board) for $12 each. Hard to beat.
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Rich Webb     Norfolk, VA
Reply to
Rich Webb
Thanks both of you for the feedback. Both of the fabricating services here are for large-scale. I'm just playing around here, not trying to sell anything. At least, not yet, and probably not for a while.
Reply to
Daniel Pitts
Instructables has pretty good page with instructions using a jig to solder and assemble the led matrix:
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nb
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Reply to
notbob
Well, an order of 10 isn't really large scale and it costs about the same to get ten as to get one. The benefit of a real PCB is that you can make the layout -- and make changes to it -- while it's "virtual." Then when you stuff it with parts, you have high confidence that you'll get the right connections.
That said, there's nothing wrong with doing a perf board or stripboard project. Poke 'em in and wire 'em up!
Since your LEDs will probably have all anodes or all cathodes in common, you may find that stripboard is a good fit. You can get the bare boards at (among others) and there is a stripboard layout app (free) over at .
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Rich Webb     Norfolk, VA
Reply to
Rich Webb
I didn't see a way of ordering less than 100 on any of the sites listed, but perhaps I wasn't looking in the right place. The cost was over $1000 for a batch up 100, which is about 300 times my budget :-)
That's probably more likely what I should do. Never heard of a stripboard though, I'll look into that.
The problem I'm finding with LEDs is that I actually care about component position (spacing between LEDs), so the layout has to be "just right", or the LEDS are too far apart, or not lined up as expected.
Reply to
Daniel Pitts
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click "services" on the left and then select "fuzion" in the middle I guess $9 is still 3 times your budget.
there may be a way to design the board with dual purposes
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strip board has copper tracks running one direction. the tracks are usually cut into shorter lengths to suit your applicaton.
compared to bare copper the tin plated stuff is real easy to use, It costs a little more though.
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you only get one option with stripboard and perfboard, holes spaced 2.54mm apart, you can fit 5mm leds with 7.62mm spacing (every 3 holes) or if you grind the flanges off with 5.58mm spacing.
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Reply to
Jasen Betts
re
Advanced circuits has some 'standard' boards for $33 each. You use to have a minimum order of three... (so ~$100) but I notice that is now four pieces.
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'm not sure how that compares to the Seeedstudio that Jason posted.
George H.
Reply to
George Herold

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