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LED-shirt v2.0 on its way! Answered

Hey Instructablonians!

So after thinking about it for a while, I realized that my original Beating Heart T-shirt was a bit.... restrictive... as to what you could display on your glorious torso. As a result, I decided to embark on a journey to make a fully programmable 14X7 LED array display on a t-shit, which I call LED-shirt v2.0! Also, since I was making this portable and re-programmable, I figured that you should be able to go everywhere and still have some nerd "bling", so I included a charlieplexed LED binary clock.

I drew up the schematic on eagle, routed the board, etched it, drilled it, stuffed it, programmed the binary clock, then soldered ALL of the crimp beads onto all 91 LEDs and female header (it's got to be detachable). I tried sewing some of the LEDs on via a sewing machine, but I bought the wrong thickness conductive thread, and the machine kept jamming. Then I tried by hand, and it just takes too long v_v.
(I'm using Leah Buechley's method)

I'm going to order the thinner thread and find someone with a sewing machine they're willing to lend me. Until then, I have this awesome blue binary clock that I can carry around with me!

Oh, it's atmega168-based, runs @ 12MHz, and as of now runs off of 3 AA's, but I have plans to make it LI-ion compatible.

Also, I have to thank Zach for the idea to make the 14X7 matrix - it's really a demi-charlieplexed 7x7 array.

Oh, and if you were wondering, that's an aluminum rod w/ a captive ring next to the battery pack. I love lathes.



Sweet! smd? *cowers in fear*

don't cower! SMD is your friend!

..... although, I did brick the mega the first time I tried this out.... now I've got a cool coaster, though!

I did the SMD by hand, with a standard iron =)

I hate smd. Obviosly your iron has a better tip than the one I have now (need to find a good one)

I've done *really* fine-pitch (I believe the pins were 6mils apart) with a chisel tip.

The trick? Don't worry about bridging, use a liberal amount of solder, and even more solder wick after ;-)

My dad's (mine is 1200 miles away in MN) is completely rounded over

Its already been ground down too far, besides i don't need to do smd

My trick is..... don't actually heat the pins (at first)! I make my traces really thin going to the SMD pads, but they widen after a bit. If you heat the traces, not the pads, it's REALLY easy. After you're done applying the solder, just wipe off your tip and heat the pins, to make sure you have a good connection.

If I understand correctly, you tin the pads, lay the piece down, then apply heat, so there isn't enough solder to bridge. I do that too, but sometimes the pins don't want to coroporate.

I also add more solder, while heating the pads - if you feed the solder into the pins, that ensures that you have a good bond =)

Also, and I'm sure you do this too, I tack the corners down first - they're the easiest to get in place.

My tip used to not be able to solder SMD. I took it to the grindstone, though, and now it can! Just make sure that as soon as you grind it down, you heat it up and IMMEDIATELY tin it, it should be (almost) good as new!

Do you etch your PC boards at home?

Mhmm! I use the popular heat-transfer method and either Ferric Chloride or Cupric Chloride as etchant. (cupric chloride is re-usable after oxygenation via hydrogen peroxide)

I have been waiting for this...


Even your original was too complicated for me (I'm not much with LEDs), this will surely be awesome!