Hi Everbody (as Dr. Nick would say)!
I would like to add a blinking LED ‘beacon’ light on the top of my N scale Kato Sd40-2 with a #1806 MRC sound decoder. The sound decoder does not have extra solder pads for function wiring, such as LED ditch lights or beacon lights. Does anyone make a standalone and small enough light only decoder to add onto the MRC sound decoder? If so, how would I hook this stand-alone light only decoder to the MRC #1806 sound decoder?
The only LED that is going to be suitable for an N scale beacon would be a surface mount device. The smallest regularly sized and easily acquired LED is 3mm, which is way too big for N scale.
A function only decoder, available from Digitrax or TCS, with its input wired to the MRC decoder’s input, would be the only way to add a flashing beacon – if there’s room for it.
Space is going to be the biggest challenge to a project of this type.
http://www.digitrax.com/prd_statdec_tl1.php
The Train Control Systems FL2 function only decoder seems to be larger than the Digitrax decoder, and is also more expensive because it offers 2 functions instead of only one.
So with the function-only decoder you mentioned, and looking at the instruction manual posted at the bottom of the link you mentioned, does that mean that I just have to hook up the red and black wires of the TL1 to the Kato pickup clips on the side of the locomotive (as inputs to the decoder), and then hook up the white and blue wires (as outputs) to, say, a small surface-mount LED, and it should work?
Basically, yes – but one more thing that is going to be necessary is a 1,000 Ohm resistor between the decoder and LED. And a surface mount LED is microscopically small and difficult to solder wires to, so you may be better off finding one with wires already attached, such as those sold by Richmond Controls. And the function only decoder must be programmed to flash the LED as desired, so make sure the decoder you select can be programmed for a strobe effect.
LEDs are also polarity sensitive devices, and if you connect the wires backwards it won’t work – you must know which side is positive and which is negative. Unless you have electronics experience or training, and the proper tools for soldering to surface mount devices, this is not a project you should undertake.
Cacole, thanks. Yeah I knew I had to add a 470-ohm resistor on the positive side of the LED. I do have a fair amount of experience solding things, as I’ve been doing it for roughly 15 years. I’m an engineer by trade, so I know about the electronics stuff.
I hope to undertake this project within the next month or so. I may even be nice enough to post a video of how I did it on Youtube…
Well I did it. I was able to add a second decoder to my N scale Kato SD40-2 for the working beacon light. It took some ingenuity, but I was able to make it work.
I took some photos of my work, and I hope to write an article in a Model Railroader in the very near future. Not sure what kind of pictures MR will accept (mine were taken with a 12.1 MP digital camera), but if MR doesn’t publish this article, then I’ll post a lot of pics of what I’ve done so you all can see what I’ve done and can copy it.
Anyone know how I can get in touch with an associate editor for MR?
Congrats on the install.
Good Luck with the article. Believe it or not that type of thing is done all the time.
Cacole, You can get much smaller LED’s than 3mm. I’m currently using 1.8mm for my signals. Just do a google for the size you want. Try 1mm and you’ll find plenty of hits.
Yeah I know, just not in N scale. I have never seen an article in MR about adding an auxiliary decoder and adding a blinking beacon light in N scale before. I want to write an N scale article on how to do that. Hopefully I can do that.
In the MR mag, there is a column that lists the personel at MR. At the bottom of the list there are contact emails for the departments.
Thanks Jay!
Hi everyone,
I finally got around to take pictures of my TL1 decoder install. If I can put up pictures, I’ll explain what I did.
The first picture I took is of the Digitrax TL1 single function decoder next to the shell of the Kato SD40-2. This engine already had an MRC #1806 sound decoder installed. I wanted another decoder to activate a simulated rotary beacon found on most Santa Fe engines.
This next pictures are the Kato engine taken down to parade rest. You have to gently grasp both sides of the shell and gently pull it apart. Make sure you don’t damage the pickup clips when you pull the shell apart.
The next seven pictures show the metal weights. I planned on putting the TL1 decoder on the rear weight under the speaker. It’s the perfect place for it.
The next three pictures show how I drilled a hole for the simulated rotary beacon. I used a #61 (0.039 inch drill bit to drill a small enough hole just for the wires of the light. The light that I used was a 1.5V 15mA 1.2mm diameter Miniatronics light bulb (part number 18-001-20) for the simulated rotary beacon. I did not use an LED because I would have had to build a small clear enclosure for it.
When I put in the light, I had to drill a small hole through the ligh
Wow…
Bending PC boards is never a good idea…
David B
You’re right. The picture exaggerates how much it is bent.
Very nice installation. I’d have never thought it would fit.
No offense to our hosts, but your article may be published quicker by N Scale or N Scale Railroading mags. They are always looking and they pay too.
Martin Myers
Martin, thanks for the reply. I may have to try that. Not that I mind the money, but it would be cool to see one of my articles published.