The wide-disbursement surface-mount LEDs definitely work well for passenger car roofs and other general illumination scenarios like building interiors, etc. where you want to light the interior but not necessarily see the light source that's illuminating it. Where they fall short is when you want to use them in an application where you physically see the bulb, and need the LED to look the part of a light bulb. Locomotive headlights would be a prime example, or marker lamps where you need the light to shine specifically out of the side of the LED. That's where scuffing the outside of a "traditional" LED has distinct advantages. You get very "bulblike" light disbursement, the prototypical look of a lightbulb, and all the benefits of an LED.

Greg, is there a particular brand or style of LED christmas lights you're seeing that are using flat or concave-ended LEDs? The ones I've encountered use a "traditional" shaped LED, and then use a separate plastic cap over that to shape the light. I'd love to play with other styles if they're available. They'd be shoe-ins for signals, class, and marker lamps.

Now's certainly the time to investigate the various LED Christmas lights. Keep your eyes open for the packs of replacement LED bulbs, too. The cost per LED is typically still a bit more than buying a complete strand, but you don't get all that wasted wire. Also look for stores that offer rebates for trading in the old incandescent strands of lights.

Later,

K

No particular brand, just open them up and look at the LED... Nick sent me a few last year that are like this...

Greg

Cool. I'll keep my eyes open for them.

Later,

K

I just got a card with some plastic Christmas bells on it, silver ones should work fine for reflectors.

The problem is that with the beam coming out of the end of the LED, there's nothing to reflect back forward.

An incandescent bulb emits in all directions, but unless you get the type of LEDs I have been talking about, a reflector basically does nothing.

Try it yourself with a "standard" LED, you will convince yourself of what I am telling you. It's an easy experiment.

Regards, Greg

Just buy the square topped led's with the dimple in the middle!! Menard's sells em out here. box of 35 for either $4.00 or $6 i'ts one or the other. Regal

http://www.homestead.com/Largescaletrainshops/
For reflectors I used Hubble Flashlight modules # 2202-2A-LM which are available
at Home Depot for around $3.98 each.

The problem is that with the beam coming out of the end of the LED, there's nothing to reflect back forward.

That's where the scuffing comes into play. Take a look at my column I think two issues back in GR, where I show a photo comparing the light patterns of an "untouched" LED, one that's been scuffed, and an incandescent bulb. The latter two are very similar, and the effect when put in a headlight or class lamp is very realistic.



All three lights are LEDs that have been scuffed. When I put an un-modified LED in the class lamps, the light was barely noticeable since it went mostly out the top. Once I scuffed them, I actually had to tone them down a bit with a brown Sharpie marker to cut the light down a touch so not to be as bright as the headlight.

Later,

K