smd LEDs call me crazy

[cteno4]

ok call me totally crazy. i just picked up 1000, yes 1000, smd LEDs for about $30. the little mites are 1.6mm x 0.8mm x 0.4mm. these will be fun to see if i can get them to work, soldering these puppies aint easy but i figured i couldn't pass this up and see if i can solder leads onto them, at 3cents each i can practice some... i can then light to my heart's content! figure these little mites should make nice discrete light sources for buildings. at this size could even do street lights!

cheers

jeff

[KenS]

I've been thinking of experimenting with small LEDs.  I'd be interested in a report on your experiences.

[Martijn Meerts]

You bought the big version of the LEDs =)

They're actually quite easy to work with once you get the hang of it. It depends greatly on having a good soldering iron (of course), but also what type of wires you want to solder to them. I like using the 0.1mm and 0.05mm copper wires with a layer of lacquer isolation. They solder on to the LEDs easily, and if you paint the wire grey or black you can even use them as visible electrical wiring ;)

[CaptOblivious]

Hell, I've done soldered SMD LEDs with a cheap-o Radio Shack firestarter. So I wouldn't even say it requires even a mediocre soldering iron. It does require a steady hand and a good "third-hand" of some kind, be it the sort on a metal stand, or a judiciously applied piece of tape.

[Martijn Meerts]

Well, true ;) But a better soldering iron means no real need for a 3rd hand. I just stick the LEDs on a bit of double sided tape or blutack ;)

[cteno4]

Thanks for all the tips! i have a decent temp controlled iron, but will need to get a micro point for it, i have a small one, but these suckers are tiny! luckily it looks like their design has the leads nicely exposed along the bottom and part of the sides of the two long ends. some of the smd leds i looked at had very tiny contact areas for their size. was planning on trying the lacquer coated copper wire. i use to have a huge supply of 2 conductor stuff as a kid. my father was a ship research captain and one of the disposable temp/salinity probes they used on the ship had 2 mile of tiny tiny 2 conductor stuff in them and usually there would be a few thousand feet left in the cartridge. i use to wire up slot card with it and then run them all the way down the street for blocks! i think i still have one cartridge somewhere in the basement, bet it has a layout lifetime of wire left in it!.

Martijn, how do you remove the lacquer insulation for the leads. i use to burn it off with a match when i was a kid.

was thinking of using lower temp solder as well as the joint does not have to be as strong as normal ones that would take more beating.

these are a grab bag of a range of whites from warm to bright so ill need to sort them some so ill make a little testing stand i can put them on to measure the 'whiteness' and sort.

ive been looking around for smd leds and really couldnt find ones i was happy with for less than about 50-75 cents each or up to $1 with leads, then stumbled upon these on ebay so thought i would take the gamble.

cheers

jeff

[Martijn Meerts]

Martijn, how do you remove the lacquer insulation for the leads. i use to burn it off with a match when i was a kid.

I pre-tin the lacquer wires just like any other regular wire. The lacquer wires just require a bit more heat, around 400 degrees celsius should work.

I initially used a flame to burn it off as well, but sometimes it didn't burn off the insulation completely, sometimes the wire just turned to coal ;) A nice side effect of pre-tinning is that it makes it much easier to solder the wires to the LEDs as well.

[cteno4]

I forgot the other thing i was going to try out was using conductive paint to attach leads. i have some which is great for odd things with small contacts or where you cant get at something easily. double stick tape may just do fine to hold both the led and the wire for either gluing or soldering. could always come back with a tooth pick dab of glue after wires are in place.

cheers

jeff

[cteno4]

Martijn

thanks, yes im a big pre tinner! i actually usually like to tin both surfaces if its easy then just do a bond weld. find i can get things done with the iron on the surfaces a lot shorter than doing a non tinned solder and usually can position things much better. on the smd leds i dont think i want to try to pre tin their leads tough. i can experiment a lot though at 3 cents each!

im wondering if using flux directly on the led contacts and good tinning on the lead will be the fastest and cleanest way to get the solder to bond to the led lead. usually im lazy with most larger things and use rosin core solder and that does fine. any thoughts here?

thanks mucho

jeff

[Martijn Meerts]

I pre-tin the contacts on my LEDs, unless I'm soldering them on a circuit board. It's not too difficult, and it makes wiring them real easy.

I don't use flux, but I do tend to use lead free solder meant for small electronics. It's worked fine for me so far.

[inobu]

Can post this link enough when discussing soldering smd.

<a href="http://www.youtube.com/v/3NN7UGWYmBY" target="_blank">http://www.youtube.com/v/3NN7UGWYmBY</a>

Inobu