Come to the dark side... (We have fancy lights!)

I've been wanting to play more with LEDs for lights.  Up to this point, I've only used the bigger LEDs from Miniatronics.  A couple of weeks ago I ordered a selection of surface mount LEDs from Mouser Electronics so I could play around with different sizes and colors.

From left to right:

• 0201 size "white" LED (no color temperature given)
• 0402 size, 4000°K
• 0603 size, "InGaN" color (not sure of exact temperature, but appears to be around 4000°K)
• PLCC-2 size, 3000°K
• PLCC-2 size, "Warm White" (data sheet shows around 3000°K)

The two PLCC-2 sizes have slightly different dimensions despite having the same case style

I tried soldering some test wires onto the 0402 LED, but ended up destroying the LED.  I was having problems with that particular iron tip and solder combination.

Given the difficulties with the 0402 LED, I never even bothered with the 0201's.  I couldn't even see the cathode indicator mark on the back!

The two PLCC-2 LEDs have a similar warm color, more closely resembling an incandescent bulb.  The 0603 is a bit cooler for my liking.

I selected the LED on the right for the locomotive because its size would allow two LEDs to fit side-by-side inside the shell, each centered on a bulb hole.  Also, that was the one size that I happened to order enough of for this project.

​The SP units have both headlights and gyralights on each end, so I made up four sets of LEDs. Each set consists of a pair of LEDs soldered together in series.  I stuck a piece of double-sided foam tape on my work surface to hold the LEDs while I soldered them together and attached the wires.

Use the datasheet to draw a quick-reference on the package showing how the anode and cathode are marked.  in this case, a small notch identifies the anode (+) lead.  For wire, I used multi-color 30 AWG solid conductor wire-wrap wire from Amazon. A 250m spool of 8-conductor wire is around $11.00.

The entire LED and wire assemblies can then be glued up inside the shell, right against the light holes.  Canopy Glue has become my new best friend.  It starts out with the consistency of white glue, but dries (almost) clear.  I used it to glue the assemblies in place.  Once dry, paint everything to prevent light from leaking out and into the cab.  The red emergency gyralight part on this model is a solid casting, so I didn't bother to drill it out and light it up.

Since this model originally came with bulbs, there were no clear lens inserts.  Again, Canopy Glue to the rescue!  Simply place a drop in the outside end of the light hole.  The glue forms an outer skin fairly quickly, so if you tease it for too long, you'll get an odd lens shape.  I simply work it until it's a flat surface.  As it dries, it will go slightly concave.  You can either leave it as-is or go back an add another drop so it dries with a more convex shape.

The decoder "universal" mounting holes don't always line up with the screw holes in the frame.  When this happens, I make a small carrier plate from .030" styrene sheet.  As a bonus, the styrene also acts as a mounting support for the speaker.  I soldered all of the wires directly onto the decoder board instead of using the little plastic wire clips.  That way I have a much more reliable connection.  If I ever need to take it apart, I'll probably be near my soldering iron anyway so unsoldering wires won't be an issue

Finally, tuck all the wires in and put everything back together. After using DecoderPro to configure the functions, we have a new switcher ready to work!

Craig

​

201s

Holey shirt!!!  Need a microscope to see ‘em!!!

Nice job! LEDs are a lot of fun to work with.  That they don’t make heat is great!  Canopy Glue is one of my go tos also.

Enjoy and enjoyed!

Nick

Electrically conductive paint and epoxies

One idea I had for working with the smaller LEDs was to use some sort or electrically conductive paint instead of trying to solder leads.  Just glue the LED and wires in place and paint the connection between the wire and contacts.  While doing a quick Amazon search, a number of conductive epoxies popped up.  That would be cool because you could simply glue the wires to the LED before installing it.

I think the 0201's would be great for things like caboose side lights, underframe and step well lights, etc.  Probably the only way to work with them would be to figure out their orientation in the tape strip and then when picking them up, don't. breathe. at. all.

Craig

I'm a glutton for punishment...

I figured if I bought all those LEDs, I should at least try to solder some test wires onto them.  Out comes the solder paste for some fun.

For the 0402, I thought I'd try to use the hot air rework nozzle on my soldering station to heat the paste.  However, that didn't seem to work.  I think I ended up overheating and damaging the LED before the solder actually melted, so back to the iron with a small tip.

It took about 5 of each of the 0402 and 0201 LEDs before I actually got one to stick to the wires (without losing it first).

The smaller ones are all too cool for my liking, so I'm going to need to keep looking.

The 0402 is actually a side-view LED, so its light pattern is different. The 0402 is 4000°K and the 0201 appears to be a similar temperature.  The 0603 looks a bit warmer so I think it might be around 3500°K.

My conclusions:

• Around 3000°K appears correct for an incandescent bulb
• Pay attention to the datasheets and the location of the solder pads
• Prefer LEDs with solder pads that wrap around the side.

Craig

Decoder

Nice job on the lighting!  I'm curious what kind of decoder you used.  I have the same model and I'm standardizing on ESU Loksound.

-Lou

I'm standardizing on ESU as well

@Lou, The decoder I used is a Loksound Select Direct.  I've started preferring the "drop-in" decoders over the ones with wiring harnesses. I find it easier to keep the wiring neat and tidy and the PC boards keep wires away from the flywheels and other moving parts.

This particular decoder I had left over from another project, and it had the GE 16-FDL sound files loaded in it.  That MP15 sounded kind of odd burbling away like a U-Boat!  I had several other decoders that needed updating so I recently got the LokProgrammer.  Now it sounds much better!

Craig

I buy 402 and 602 with wires already attached

I found a source on EBAY that seels both the 402 and 603 for about $9.00 for 10 pieces including 1 K resistors. This is a bargain for me as all have to do is strip the fine wire to solder it to the decoder. Saves me time and frustration. To dim these down you might wan to vary your resistor value between 1 and 3 K. You can also use  a very thin coat of Tamiya clear yellow or orange to give these LEDs a more natural color and dim them slightly. I use Eileens tacky glue available at most craft store and Walmart to glue my LEDS.It dries clear and is water soluble if you ever need to change the LED or lense

Great job on your MP15 BTW.

I forgot to add that I am a switching everything I own to TCS WOW sound. 

Gary

Yep, buy em with wires attached

I'll need to go looking for those pre-wired LEDs

At that price, it certainly is cheaper than doing it yourself, at least with the smaller ones.  For me, the 0805's and larger are still fairly easy to solder wires on.  But those 0402's and 0201's...

At least now I've done it once, so I can fully appreciate why I would only want to do it once! 

Thanks to everyone for the kudos! I've been tweaking the motor settings and now it both runs and sounds awesome!

Craig

Decoders and LEDs

Craig,

I use drop-in decoders where possible, and I agree they make life much simpler!  I've installed a variety of sound decoders including TCS Wow Sound, Tsunamis, and Loksound.  I'm loving the Loksound decoders with TCS a close second, so all future installs will be ESU or TCS if I can't find what I need in ESU.

I'm in the middle of wiring a Loksound Select into a brass model of the Timken Four Aces.  I ordered the decoder with the sounds from UP 844, and wired the headlight and tender light with 603 LEDs which fit quite nicely in the headlight castings.  I used MV lenses so the headlight has that nice, prototypical look, even when its off.  I ordered a bunch of 603s, pre-wired with 1K resistors from Ebay but got burned on the color temperature so Tamya orange paint to the rescue!

Again, that MP-15AC looks great!

-Lou

I found and ordered some pre-wired LEDs

I went perusing through EBay and found some of the pre-wired LEDs that Gary and Joe mentioned.  At around $9.00 for a pack of 10, that's a good price.  I found a couple of suppliers that sell 20-packs for around $15.00. That's a great price, so I have a 20-pack of warm white 0402's on the way!

The Tamiya clear orange paint sounds interesting. I'll need to get a bottle to play with.  From your experiences, are there particular temperature ranges where you find the yellow paint works better than the orange paint (and vice-versa)?

Craig

Soldering SMDs

First off, ditch the regular blue and white wire you have.  Really do best with enameled magnet wire.  It's a little tricky to learn how to use it but once you get the hang of it, there's no going back to regular decoder wire.  The two sizes I use are 32 AWG and 36 AWG in red, green, and copper.   Red is strictly for the positive side of the LEDs and the green or copper is for the negative side.  As for resistors, I use 1/8 watt 560 0r 680 ohm.  Both seem to work well and the headlights are nice and bright that way.

I make these "resistor boards" to make wiring simpler.

Blue wire goes to "function common" and you would attach your positive red wire to the resistors.  I try to use 1 resistor per LED so this board here will do 4 lights.   Just add more resistors for more LEDs.

P.S.  Don't really ditch the wire you are using but in this application when using 0603 and smaller LEDs,  the magnet wire really shines in this case not to mention how much room it will save when putting the shell back on!

I second the magnet wire. I

I second the magnet wire. I bought several hundred warm white 0402s and it took a few tries but I have no problem soldering to them now. Not sure I could do anything smaller. In my younger days I regularly soldered SMDs with no magnification or extra light. Now I need glasses, optivisor and strong lighting.What a drag it is getting old. 

More adventures with LEDs

With everyone recommending the pre-wired LEDs, I hopped on eBay and found a 20-pack of warm white 0402s for about $15.  At only 75 cents each, I don't think I could do them myself that economically.

Recently I thought I should go through my locos and select some to install decoders.  To my surprise, each one I pulled out already had a decoder installed!  I guess it was so long ago I had forgot that I already decoderized a bunch of them.  However, I never got around to installing the lights, so this proved a good opportunity to try the new LEDs.

Upper left is a bundle of the pre-wired LEDs from eBay.  On the right are a couple of Details West rotary beacon parts, drilled out and another LED glued in.  Just below is the LED I found at Mouser that is a perfect size for the beacons (Lumex part SSL-LX203CYT) - just drill an .080" hole in the beacon base and glue it in. On the bottom are two sets of LED headlights.  I elected to wire them in series to minimize the number of wires I have to deal with, and using a 1k ohm resistor they're still plenty bright.  The two wires that I clipped off when wiring them in series were then used as leads on the beacons.

Here's everything installed. To hold the headlight LEDs in place, I use little bits of AMI Instant Roadbed material.  It's a gooey tar-like material that has all sorts of uses. The beacon fits in an .080" hole in the roof, and the leads are bent over and taped down with kapton tape to keep the beacon assembly and other wires secure.

Over the last week or so I've completed lights in 8 locomotives.  I think this has been the easiest way to install headlights and working beacons that I have found so far.  Now it's time to stock up on more LEDs!

Craig

Hi Craig

Gotta love those wired LEDs!  Something I added and found very useful later were the smallest JST plugs I could find.

Number boards, headlights and ditch lights front and back attached to side coded JSTs and a soldered ground are very quick when one bounces off the floor!

Hope all is well with you.

Nick