I love the idea of adding lighting and it's detail to a layout. I know LEDs are the way to go and this article has answered many questions. Joe I love your magazine!!

Gary

I loved the article.  I've been wondering for some time how to get lights into some really tight places.  Now I know!

Great article, Dr. Geoff. Nice job taking the mystery out of installing and working with these little buggers. I'm a few weeks away from lighting a large structure and this is the route I'll be going. Got this one bookmarked! Thanks!

Yes, Dr. Geoff did a good job on this article. For more help/tips using SMD LEDs - both soldering and placement, see the "My Modular Adventure" column by Les Halmos in the MRH Mag Issue 13 and 15, March and May 2011.

I had forgotten about those articles, Bill.  There's a video in the May column, too:
http://www.youtube.com/watch?v=U3VhPQMqHfI

G'Day Geoff,

Good article and thank you for mentioning my book on 'how-to' with SMD LEDs -

http://www.quickpicbooks.com/MMR/Electric/SMLED_1/SMLED_Book.html

 My Y-Tube videos show how I solder 0603 and 0402 LEDs plus lots of other animations and sound.

I now install the resistor inside the body of the HO figure using a SMD resistor.

Also I use Carr's orange liquid flux (non-acid) which is a must for soldering the SMD LEDs.

I have been asked to give clinics on my lighting and animations at the 32nd National Narrow Gauge Convention in Seattle this September and will have several of my models to demonstrate.

Regards,

Laurie McLean MMR

Australia

Just thought I'd jump in and share a couple of videos I made a little while ago that show techniques for LED soldering. Apologies that there is no sound on them. I usually talk over them while presenting a structure lighting clinic.

The first clip covers the task of tinning magnet wire. Here i use an iron with a 35W element. It gives me the hot temperature needed to melt the insulation and tin the wire at the same time (700-800 degrees F). Later on I switch to a 45W element and show what a little too much heat does. you'll see that I stab the blob of solder with the end of the wire. Just like popping a balloon. I do it at normal speed and then show it again in slow motion instant replay.

http://dl.dropbox.com/u/9483972/1-Tinning.wmv

Next is a  video clip showing how I  solder the wires using the type of holder mentioned in Dr. Geoff's article. I think I had about six cups of coffee before actually filming this clip. I should re-shoot the clip because after soldering a few hundred of those buggers my skills have improved.

http://dl.dropbox.com/u/9483972/2-Soldering.wmv

That clip showed a solder method we call "back soldering." The wires can be simply twisted together and inserted into a lampshade and tubing. Les has his wires coming in from the side (side soldering) and another way has the wires coming over one end (end soldering).

When I first started soldering I used sticky-side-up tape as does Laurie and Les. Perhaps I didn't have the right tape but I got tired of chasing that darned LED all over the place with the soldering iron tip. I like the LED holder gizmo better but as they say...to each their own.

I'm going to be cobbling out a book on the subject and hope to have it done later this year. Guess we can't have too many books, tools or kits to choose from eh?

Laurie - good luck on the clinic this fall. I had a blast doing mine last September.

Bill - Get to work!

Have fun and don't burn yourselves.

Bill S. (aka Slim Jerkins)

I just skimmed this article, but I can already see improvements to the techniques I use in working with SMD LED's.  I got my feet wet making up some 0603 lunar signal lamps.  All were successful and are still operating on our club layout.  I want to do more lighting projects and this article will help me accomplish them.

Ron F.

http://www.ida.net/org/pmrhs/

A alternate to the CL2 is a CLD20B.

Steve

Thanks for the CLD20B add Steve. I found that one after I wrote the article. There are a couple others too. I like these even better because the package is easier to work with.

There is a strange issue with current limiters: the rating for the reverse voltage is quite small <1Volt and the reverse voltage ratings for many leds are also quite small-- but every CL regulator and led combo I've actually tried (the pair alone)  work great with DCC-- but they shouldn't! So for good design practice I've added the "rectifier" diode listed in the diagram-- whose reverse voltage rating was usually greater than 30V.

Strange, but true.

I use the current regulators because I like to run the tiny leds bright--my personal preference here.

Geoff Bunza

I'd also like to add my thanks for this article - a fascinating subject, well explained, with clear photos and useful links.

I've enjoyed messing around with LEDs for many years (at least since the mid 1980s, when I was an electronics student at the Polytechnic of Wales). However, I've never really worked out how to fit and wire surface mount LEDs - so this fills a gap in my knowledge.

I'm not sure this would interest many people here, but one guy on the UK site modelrailforum.com recently posted a number of photos showing the use of conductive paint for running connections to surface mount LEDs fitted to model figures.

I'm not completely convinced by this idea - but I wondered if it might be worth mentioning in case anyone here has experience of it.

Anyway, thanks again Geoff for the article - and thanks everyone else for the discussion that's followed it.

All the best,

Huw.

I hope nobody here minds me butting in here - but I liked Laurie's point about Carr's Orange Label Flux.

This stuff is also very useful if you need to desolder electronic components.

A lot of people probably have offcuts of cheap coaxial wire - if you dip some of the braid in "orange label", it's great for mopping up excess solder. It works just as well if you allow the flux to dry on the braid.

Anyway, side-track over - and more than enough from me for now.

Regards,

Huw.

Huw

I saw a bottle of conductive paint at the local Radio Shack. I was thinking of giving it a try but I didn't have the $20 for research. The instructions said to cure it for four hours under a 40W lamp with a full cure in 24 hours. At that point you could solder onto it with a dwell time less than 3 seconds.

I bought a roll of copper tape that I think I'll use first.

Bill

If you guys liked Points of Light, just wait until you see Geoff's next project! No date scheduled yet but I'd guess it'll probably hit a bit past mid 2012.

Charlie

Yes, using a liquid flux is a MUST when working with SMD's.

Even if the solder pads (the tiny terminals where they are soldered) look clean they MUST have a flux such as Carr's orange applied to them to deoxidize the metal - even the new ones !

Speed is what is needed to 'tin" the solder pads. If you leave the iron on it will destroy the SMD.

On the Soundtraxx group I explained that to do this SMD work you need a variable temperature soldering station.

The electronic type stations are IMO no darn good - get a soldering station with a heavy transformer inside and use a small pointed or fine chisel iron tip.

Next is don't use a wet sponge - the water cools the tip and ends up pitting the tip. Get and use a brass curly metal to clean the tip. 

The next matter is using resistors. I often use SMD resistors and these can be hidden inside the body of a HO figure and covered over and touch-up painted.

I believe TraintecLLC.com will be stocking the 0603 SMD LEDs shortly. I buy my decoder wire from this company.

If I want a colored LED I use Tamiya translucent paints to tint such as for caboose marker lamps and of course a tiny piece of Kapton tape can be super-glued onto the resin light package to give a 'golden white' illumination.

As for resistor values - 1k = bright, 3k = medium light, 8 k = dim light which I use for hand lanterns.

Now back to making working bells on my HOn3 locos (grin) ...

Laurie McLean MMR

Australia

This article is fantastic. I will be referring to this article often as I'm not adept with soldering and wiring. Thanks so much for the info.

This just might be the best article so far.  Great ideas and suggestions.