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Yard Master & Research
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Discussion Starter #1 (Edited)
One problem is the camera it adjusts the light so it changes the appearance.
I used 8 5mm LEDs at 13000 mcd with 150 ohm 1/2 watt resistor on the AC accessory terminals. They were wired in groups of four so no diodes were needed. When placed on a throttle they did fluctuate. I also used a Wendy's straw it did difuse the light. I ended up slitting it to ease the testing.



First the bulb. Then with a paper screen for the control.




Then with the straw off. Then no lights with the paper for the control.


Then with the straw and then without it.


Not much difference. The lights are better displayed with a dark setting. The key may be to get something to relfect to the windows.
 

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T-Man,
Since we are both working the same type of project in tandem, I thought I'd take the liberty of adding some input to your thread. I've been trying to arrange isolated power to those lights, i.e., not using the frame. I'm mindful both of the possible interaction between my aluminum car bodies and the sheet metal frame, and of the need to secure both ends of the circuit for your LED's.

I started by going to a LHS and buying a brass strip---I wanted copper, but this is what they had.


I should mention I'm starting with a truck for a powered car (metal wheels) that lacks the copper transfer-spring to convey power from the axles to the car. (I swapped back and forth between 2 trucks, so ignore the disappearing coupler!)
The idea is to cut it and shape it to accomplish this:


First, a blank is cut that will fit between your axles and be long enough to reach from front axle to the truck's pivot point, then down to the other axle. I overestimated the length intentionally; it's a lot easier to remove metal than to add it if you overlooked a detail.





The dimple I punched in the center with a nail marks where to drill:
Incidentally, a magnifier is a wonderful help in this kind of work:


Estimate where the first bend needs to be by centering the hole under the center of the hole in the truck (where it attaches to the frame) and mark it with a Sharpie pen or similar. Use an old wood chisel and hammer to stamp a line into the metal so it will bend in the right place. Then, hold the metal in a pair of pliers with the tip of the pliers at the bend, cut-side up. Push down on the metal and it will bend at the line. Repeat for the other side.




Now, slip a screw (I used 6-32) thru to align the strip and see how you did. The idea, now, is to determine where to bend each side a second time to have the metal end up lying flat on top of each axle. Eyeball it---it's not super-critical. Mark it with the pen. This time, you will be using the chisel on the other side of the metal, as you want it to bend in the other direction. Stamp it with the chisel, bend it, and try the fit. Adjust the bends as necessary to get the metal to ride the axle lightly.



Trim to fit better---no sense having excess weight or friction against the insides of the wheels.


Now it needs to pass thru the frame without metal-to-metal contact. The wiring for the lights will be connected directly to the shaft of the screw and clamped between two nuts. To ensure it was insulated, I went to the trash can. I found a container, clear plastic, for cherry tomatoes. Using a quarter for a template, I cut out a pair of rough circles for insulators. One goes between the truck and the car's frame; the other inside the car, between the frame and the nuts that secure the truck and wiring. I then took two sizes of heat-shrink tubing and cut two pieces. The smaller was slipped over the threaded shaft of the screw and heated to shrink, then the second sleeved over it and heated, giving me plenty of insulation and protection against abrasion.





 

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Yard Master & Research
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Discussion Starter #3
I use the spring from a broken tape measure.
Cheep ones for a dollar are worth breaking.:D
They don't have to be wide either.
Hey excellent presentation.:thumbsup:


My coach doesn't have one axle or wheel.:(
 

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.......
I used 8 5mm LEDs at 13000 mcd with 150 ohm 1/2 watt resistor on the AC accessory terminals. They were wired in groups of four so no diodes were needed..........
I am about to do this. T-man, could you post a schematic for the circuit that doesn't use diodes? thanks.
 

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Discussion Starter #5 (Edited)
Diagram

This is for AC The HO followers can use this attached to the acessories terminals to light up a building or a non moving car.
THe premise is to solder the opposite leads of a pair together. The long to the short. The pairs act as one in AC but only one will work in DC at a time. If DC they get wired in series struung in pos to neg pos to neg. You will need a bridge . Just tell me the number to figure out the resistance.
You will need to calculate the resistor depending on the pairs for AC.


...[
 

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I use the spring from a broken tape measure.
Cheep ones for a dollar are worth breaking.:D
They don't have to be wide either.
Hey excellent presentation.:thumbsup:


My coach doesn't have one axle or wheel.:(
Thank you, T. Yours was better---my photography still sucks. I was uneasy about hijacking your thread, but it seemed they really should be sequential. My coaches are all in pieces, too----I have one intact one that I just got on Ebay. For everything else, I got the frames on one bid, shells on a second, trucks on the third, I'm making my own springs and buying couplers from the LHS. By the way, that tape-measure idea is a good one! I have a couple around the house that need to be retired from splitting, anyway. :)
 

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Discussion Starter #7 (Edited)
The difficult part to the spring is drilling the hole.
I start small. If it catches, it spins and you have a small weed eater.:eek:

It is better to start with a hole then cut and trim from there.

I guess you did some shopping.

I thought you already had the trucks.

For pictures I turn off the flash and use a closeup setting.

There were so many pictures of the coach. I fed them to photobucket on a medium setting. Then pasted from there.
 

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Definitely true on the weedeater. I've got some neat toys to control that problem; someday I'll do a brief thread with some pics of unique tools I have that are useful for train work. The tool/skill overlap between modeling, metal-work and jewelry-making is significant. I don't know squat about electronics, but I can scrunch metal. *L*
 

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Discussion Starter #9
The electronics was a climb. Everything was from on line. I kept to Radio Shack items to keep it simple. The hardest thing was identifying parts If one number or letter was off I was confused. Now I know what to get. Different manufacturers use the slightly different system. Now I can discuss all scales it is just a matter of size.

Are those repro tucks? They look new.
 

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I thought you already had the trucks.

For pictures I turn off the flash and use a closeup setting.

There were so many pictures of the coach. I fed them to photobucket on a medium setting. Then pasted from there.
I had the trucks already in the sense that I started buying parts with a vague idea of "I'm going to have some powered cars", inspired by your earlier thread about overhead illumination in cars. So, I acquired the trucks (without pickup springs); later, acquired the floor plates (thought they would fit the light Pullmans instead of the heavy-duty's---wrong!), then saw the encrusted aluminum car bodies and went for them. Obviously, I'm overdue for some sort of 12-step program. In the meantime, I also bought a nice little Pullman (all there but the lighting!) in red plastic.
I think what really launched me onto this fixation was Big Ed's Casey Jones locomotive and a statement by my girlfriend. Ed's gift is a lil high-speed beauty that only has forward; they weren't made with a reverse. The girlfriend's comment was that she really preferred passenger trains over freights because she liked imagining the people travelling. Voila! She gets a passenger train, I get to invest all the time and money that I want to because she likes it, too! *L* It was great until I saw how much passenger cars go for. So, the answer was to buy them in pieces and build them.

As for the camera suggestions, thank you. I looked up the on-line manual and I now (I think) know how to turn off the flash. Between you and Tankist, I'm going to eventually learn to take a decent photograph.:laugh:
 

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Same coach----650 New Haven. No lighting yet: I'm waiting for you to perfect it so I can copy you. *L* I think I'm going to make it the crew-car for my train-wreck train. I have an engine, crane, boom car, work caboose, and a flat car that I intend to fill with ties...that 650 would look good bringing up the rear as transport for the crew.
 

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THe premise is to solder the opposite leads of a pair together. The long to the short. The pairs act as one in AC but only one will work in DC at a time. If DC they get wired in series struung in pos to neg pos to neg. [
OK! gottcha. Thats what I had in mind, but now its clear as a bell. I appreciate your offer, but I'll experiment - my passenger cars are long and
I suspect I will use the 8 lamps per car, and I'll start with your 150ohm res. Now I really can't wait to do this :cool: THANKS AGAIN.
 

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Discussion Starter #14 (Edited)
Hope you know what you are doing

Ahh, 8 LEDs in series require 24.8 volts DC plus a rectifier to work both ways is another 2.8 volts. .7 volts for each of the four diodes. Two pairs of a series of four will be 12.4 volts each. With a bridge is 16.2.1 volts in the range of a common DC transformer. Unless you turned AC on us. Your scale says HO?

example for DC three LEDS in series is 9.3 volts plus 2.4v for a bridge is 11.7v

14-11.7 =2.3v/.02amps =115 ohms for 14 volts DC, the resistor would be 120 or 150ohms

18-11.7= 6.3/.02= 315 ohms( go to the next size up), the resistor would be 330
ohms
to play more lets say one diode but it is used in one direction so forget it.

12 volts would be ok

14-9.3= 4.7/.02= 235 ohms or 270 or 330 the next size

18v-9.3 =8.7/.02 = 435 or 470


You need at least one diode across the feed in using DC so that it will light in both traveled directions.
 

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Ahh, 8 LEDs in series require 24.8 volts DC plus a rectifier to work both ways is another 2.8 volts. .7 volts for each of the four diodes. Two pairs of a series of four will be 12.4 volts each. With a bridge is 16.2.1 volts in the range of a common DC transformer. Unless you turned AC on us. Your scale says HO?

example for DC three LEDS in series is 9.3 volts plus 2.4 for a bridge is 11.7

14-11.7 =2.3/.02=115 ohms for 14 volts DC, the resistor would be 120 or 150

18-11.7= 6.3/.02= 315 ohms, the resistor would be 330


You need at least one diode across the feed in using DC so that it will light in both traveled directions.
After reading all that gibberish, I'm just putting flourescent tubes in the ceiling on my cars. *L*
 

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Discussion Starter #16 (Edited)
I volunteered to do the math but that what it takes. The variables kill you. He never gave a single number to work with only 8 LEDs.

You can write a book on it and everyone thinks it is easy. Until you try to explain it.:eek:hwell:

I appreciate the honesty.
 

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Not a problem, T-man. My electronics training was limited to one semester of dc circuits in 1971. It would be fair to say I've forgotten some of it. Actually, I can follow the math as you explain it....slowly, and with frequent back-referencing. It makes a great pain between my ears, though. I respect the work that goes into those "simple" explanations.
 

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......Unless you turned AC on us. Your scale says HO?

example for DC three LEDS in series is 9.3 volts plus 2.4v for a bridge is 11.7v
.....
Yeah, this will be for HO.
Thats more information then I could have asked for. I just don't mind* experimenting with small circuits, but now I see how the math works, no problems.
thanks!


* - 'don't mind' = enjoy as long as I have the time
 

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Ok, This is a great thread. I have been looking for a way to replace some bulbs with LEDs. what i want to do is mount the LED and components into a standard Bayonet base. this would give me direct replacement in most cases.

I ran across this formula for those that dig formulas

Resistance(series) = (Supply Volts - LED Voltage Drop) / LED Current (Amps)

The other thing I found is that since the O-Gauge Track provides AC, then at most you will get a reduced brightness since the LED is operating on only every other cycle. To get better results a Full wave rectifier should be added in conjunction to the resister. Voltage drop would then be the LED + 2 Rectifiers.

The other thing I came across is that the reverse voltage of most LED's is 5 volts. This is well under that of the Track supply and can cause shortened LED life. The fix for this is to put a Silicon diode (1n4003) across the LED in reverse polarization. The Silicon diode can take a much higher reverse voltage then the LED, and would lower the reverse voltage seen by the LED to .06v

Going to go visit "The Shack" to see what kind of parts they have and experiment. Got to see how small of a full bridge rectifier I can find. I'll post some construction comments and photos later this weekend.

Interested in any thoughts anyone might have.
 
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