I am fairly new to the model RR world. My dad has experienced a 2nd childhood (retirement) and has gotten me hooked on his old hobby.
I am in the process of building an HO Walthers Jordan Spreader kit. I would like to add a working headlight to the model. Being ignorant of most things involving electricity (save don’t whiz on the electric fence) I haven’t a clue on the best way to proceed. The space for a bulb/LED is very tight, so would an LED be the best route? Do they make bulbs that are teenie-weenie? How would I wire it for power ? (did I mention my ignorance in this area?) I am running DC, and don’t really care about directional lighting, as long as it lights I will be more than happy :).
So what do you all think? The more specific the better!
First off, [#welcome] to the forum! Good to have you aboard! [:)]
LEDs are just terrific for headlights and they put out next-to-nothing heat. If you do use an LED, you will need to solder in a resistor (probably a 1K or 1,000 ohm) to drop the voltage down to 1.5V or lower. (LEDs are rated at 1.5Vs) Otherwise, when 12 or 14V meets 1.5V, 1.5V goes poof.
Richard, the recent issue of Model Railroader (July) actually has an article on installing LEDs, which you might find helpful. I haven’t looked at it yet but it will at least get you started. [:)] The surface mount LED may be small enough for what you want to do. You’ll need a 0.116" OD hole or opening for a 3mm LED.
Hey Tstage how’d you know the answer to my question before I asked it. I’ve installed a decoder in a P2K gp-18 and am about to install lights. I was wondering what the voltage req. for an LED was. Now I know the answer. But do some LEDs have different values? I know there are a lot of different sizes as far as diameter goes. But are you saying they’re all 1.5 V ? Also is a 1K resistor always the one to use or does it depend on the input voltage.?
Oh yeah,Reformed grownup,welcome to the forum. Is your Jordan spreader working or static? Either way you could make little flattened copper wire sliders or find some Tomalco sliders which are made of very thin bronze shim material.
It’s a static model. So I would run the sliders from the lead wire from the resistor to the rail? (in the “real world” people actually think I’m sort of bright )
I find that LEDs are either 1.5 volt or 3 volt…3 volt LEDs are usually white or superwhite and such. That being said…most LEDs will work with 1.5 volts and the 1K resistor works fine with most LEDs.
As far as diameter goes, most are 3mm, but 5mm and 1.5mm are available. Also, you can look at Surface Mount LEDs (I use them for my ditchlights and such)…as you can see, there are many options.
I’m not familiar with the Jordan Spreader model. For me, and the rest of us in my situation, could you tell us about it? Is it self-powered, or designed to be pushed/pulled? Does it have metal wheels and axles, assuming it’s not self-powered?
The typical way to add power pickups to a non-powered car is to use metal wheels. You can then add “wipers” to pick the power up from the wheels. An alternative is to use wheelsets where the wheels on one side are attached directly attached to the metal axles, while the wheels on the other side are insulated from the axles with plastic sleeves. In that case, you can use the “wipers” on the axles, getting power from one rail on the front truck, and the other rail on the rear truck where you would put the insulated wheels on the other side. Tomar is one manufacturer of wipers. I’m sure there are others.
But, you’re running DC, and LED’s are “directional.” The D in LED stands for Diode, an electrical device that only passes current one way. So, you need to wire the LED correctly. If it’s backwards, the LED won’t come on at all. DC adds another complication - When you change the engine direction in DC, you flip the polarity on the track. You can use this to your advantage, of course. If properly wired, a headlight will be on when the unit is moving forward, and off when it’s going in reverse. If you put a light on each end, by wiriing them opposite to each other you’ll have what are referred to as “directional” headlights.
Oh, and I really like your screen name. Well chosen.
I’m going the have to disagree with tstage. Not all LEDs are 1.5v. I’ve got some suface mount LEDs that do almost nothing on 1.5v, but work great on 4.5v - 5.0v. Why? because they’re made to be suface mounted on a circuit and most circuitry runs at 5.0v. Take a look at a computer power supply, one of the outputs is 12v another 5v.
That being said, I can still use a 1K ohm resistor to drop the voltage for use on track power (DC or DCC) and not burn up the SMD LED. It produces an incredible amount of light for such a small device.
I’ll agree with tstage on the point that a LED is the best choice because they put out almost no heat so you don’t have to worry amount melting the plastic housing. Your other option is a 1.5v grain of rice bulb. Very little heat output also, but you’ll require a different resistor to use track power for it.
The bigger question is how to get power to the light is the Jordan Spreader doesn’t have power pick-up. You might also want to consider adding a constant lighting circuit.
Custom built and finished (starting with parts from the Walthers kit). Canadian low front plough; all side plough joints and hydraulic piston mounts fitted with brass pins for strength, stability and full flexibility of movement; brake hose and coupler cut bar installed. Kadee couplers properly mounted; Kadee wheelsets. Lettered Modern CN squiggle, #57089 and weathered from prototype (1995) photos. MV lens mounted in headlight.
In a perfect world, some Kato Caboose trucks would light the way, but they are hard to come by. A reed-switch mounted in the roof would work well for an-on-off switch.
I do realize that. Although I was being somewhat facetious in the first part of my response, I am sincerely appreciative of learning of my error. Again, thanks for the correction. [:)]
Just thinkin about this problem a little more. If you use track power ,you’re only gonna have light when theres juice to the track. Why’nt you just use one of those little flat batterys they use for electronic stuff, get a tiny little slide switch from radio shack and wire the LED into the battery with the switch and hide the switch on the model somewhere? Forget about the resistor if you use a 1.5 V batt.
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