I <3 SMD!

vb_master · Post by **vb_master** » Tue Dec 06, 2005 8:41 pm

Today I built this LED that displays 16,777,216 colors! It is on a PCB less than an inch long, and about 1/2 an inch wide. It was pretty tough to build.

So does anyone else know how to solder SMD?

Sorry, I'm just really proud of this RGB LED right now!

Post by **Skyone** » Tue Dec 06, 2005 8:45 pm

Nice man! Ya, I've only soldered a coupple SMD's really well. I usually use solder paste but sometime I go out on a limb and solder SMD with real solder.

vb_master · Post by **vb_master** » Tue Dec 06, 2005 8:47 pm

This is a link to the kit, mine looks exactly the same, but with a 9 volt clip.

Post by **Triton** » Tue Dec 06, 2005 9:01 pm

i say you make a few thousand and build a controller for them and have a super low resolution display! that would be awesome, or hire a few dozen people and make about 20 thousand! giant LED screen lolo

Post by **gannon** » Tue Dec 06, 2005 9:09 pm

I've never heard of SMD, what is it?
Unless you mean SMT

or they happen to be the same

Post by **bicostp** » Tue Dec 06, 2005 9:17 pm

Nice! I thought Kevin Horton did something like this once...
blahblahblah/commerce.exe?preadd=action&key=SBRGB

^That commerce.exe worries me a bit.

Still, that's pretty cool.

Post by **Skyone** » Tue Dec 06, 2005 9:30 pm

bicostp wrote:blahblahblah/commerce.exe?preadd=action&key=SBRGB

^That commerce.exe worries me a bit.

Still, that's pretty cool.

Oh crap. Didn't notice that. I didn't even think an exe could be used as an active online page.

timmeh87 · Post by **timmeh87** » Tue Dec 06, 2005 9:32 pm

i have always wanted to try to build myself a display with RGB leds. this is definitely a good first step if youre up to the challenge!

as far as soldering surface mount chips, its something that requires practise. go though your old computer parts, and find something that works, but you dont want anymore. pick a surface mount chip that looks about the level of difficulty you are looking for, desolder it, then solder it back on! if the board still works, congradulations! my first 3 didnt!

i find that if you just apply small amounts of solder at a time, you can touch adjacent pins and it wont bridge the gap. this has led to my technique of just stroking 4 or 5 pins at once with my iron for maximum haste!

once youre done, follow up with a multimeter. make sure you know which pins should be shorted ahead of time, to avoid headaches. "crap. these pins are shorted! why! they dont look shorted! ive been at it for hours! oh wait... they are both ground pins..."

a pointy blade with a handle is useful for this kind of work.

vb_master · Post by **vb_master** » Tue Dec 06, 2005 9:44 pm

Yeah, that's Ramsey's site. I think you can trust them, they are good.

I see these signs on the road. Like HUGE screens, look like 1000's of RGB LED's in them!

The blinky kit is based on a PIC, so it's pretty customizable (the manual even has snippets of the code!)

Post by **Skyone** » Tue Dec 06, 2005 9:45 pm

Ya, I always see LED Signs in Las Vegas. Pretty crazy, I actually have to stare at it until I see the LEDs.

vb_master · Post by **vb_master** » Tue Dec 06, 2005 9:46 pm

Skyone wrote:I actually have to stare at it until I see the LEDs.

I would like to see if you could hook up a compisite input to one. They are probably running on computers hooked to the internet. Who would ride around and update the ads everyday?

Post by **Skyone** » Tue Dec 06, 2005 9:48 pm

I actually don't doubt they have a composite in. It's actually usually a video advertisment repeating.

superdeformed · Post by **superdeformed** » Tue Dec 06, 2005 9:57 pm

SMD = surface mount device(s), SMT = surface mount technology; kind of but not quite the same

. Anyways, I solder surface mount parts all the time, but I generally have access to a hot air pencil, a heat bath, and solder paste when I do it. I have hand soldered 144-LQFP (just over .75 inches on a side) parts before, but it's a lot easier than it sounds when you have practice. The smallest surface mount parts I've done by hand are 0402 resistors/capacitors. Those are a bit trickier, as they're only 1mm long and .5 mm wide! A fine tipped soldering iron and pointy tweezers do wonders for stuff like that

.

Post by **marshallh** » Wed Dec 07, 2005 3:58 pm

Hm.. interesting find. I did a similar project with 3 leds (red, green blue) and used a pic16f628 as a PWM controller, with a cap. It was cool (Maybe i'll build one for my SNES jsut to have a cool light :p)

timmeh87 · Post by **timmeh87** » Wed Dec 07, 2005 4:45 pm

we bought LED christmas lights that fade from red to blue. due to the PWM thats going on, if you shift your eyes while looking at them, you will see the opposite colour for a brief second. its kinda freaky and hard to look at for too long.

what do you use for a pic programmer marshall?