Has anybody found a contstant-brightness headlight circuit (either board or hand-built) that would fit inside N-scale locos? I’m just getting started in that scale, due to job travel, and have not yet committed to/invested in DCC. Any help or ideas would be appreciated.
Thanks!
Don
There should be enough room for the diodes. If you don’t want to build your own, Utah Pacific and Minitronics has a fairly compact board w/ the diodes. Check them out If there’s room for a decoder, these should fit.
Bob K.
Give this site a look. http://www.pollensoftware.com/railroad/circuit.html
Thanks for the reply, Bob. Actually, I would prefer to build my own. Most of the devices I’ve seen use an IC of some sort, or are potted so you can’t see what they consist of. I thought at one time there were some schematics in an electronics project section of Model Railroader, but I can’t find them any longer. Anybody have ideas how the circuits are built [?]
Thanks again for your help[:)]
Don
The circuit from pollensoftware.com is exactly what I was looking for. Thanks Ned[:D]
To Don Frey. Jameco Electronics at www.jameco.com is a good source for the LM334.
Use a 4.7 ohm resistor for 15ma, 6.8 ohm for 10 ma, and 10 ohm for 8 ma. Hope this helps.
[quote]
Originally posted by nedthomas
To Don Frey. Jameco Electronics at www.jameco.com is a good source for the LM334.
Use a 4.7 ohm resistor for 15ma, 6.8 ohm for 10 ma, and 10 ohm for 8 ma. Hope this helps.
Thanks, Ned. I appreciate your help. I’ll try Jameco for the parts needed.
Don[:)]
You can even do the www.pollensoftware.com solution in N scale using surface mount devices. I bought the LEDs (and some magnet wire) from www.ngineering.com, and the ICs and resistors from www.mouser.com. The resistor is p/n “260-4.7-RC” . Solder the resistor between pins 2-3, run a magnet wire from pin 3 to the top of the IC, solder the magnet wire to one end of the LED and a 24ga copper wire “post” to the other end of the LED. Bind everything with epoxy, and substitute it for the headlight bulb. It required some cramming, but I was able to swap out the bulb in my new Life-Like FA-1. Remarkable difference.
I like the pollensoftware solution to constant lighting. But I’m new to electronics and was wondering if you could attach two additional LEDs to one circuit for ditch lights or do you need a circuit for everyone LED.
Also, why is Magnetic wire suggested?
Thank you
The magnet wire is almost as thin as a human hair. I used it to keep the size down. You could use thicker wire, up to doorbell or phone wire size (~24ga). I chose the magnet wire to keep the assembly small. Since the IC provides a constant 15ma current, you could probably wire the headlight and ditch lights in series (+)->IC->LED->LED->LED->(-).
Wire used to “wire wrap” printed citcuit boards is also good. It is #30 wire.