LED headlights?

[der5997]

rocky451: Thanks for that heat shrink tip for keeping LED light out of the loco cab. ( I guess you don't use your lighter for shrinking that? [;)] )

[der5997]

higssy: " Should the fibre optics be available at the local hobby store or am I looking at Radio Shack or something like that?" (haven't figured out how to quote in this Forum yet )

OK, your LHS should be able to get plastic fibre. However, there's a cheaper way to go. You know those table lamps that have fibre optics sprouting from them like a small bush? They were a fad some time ago. Fads end up in yard sales. Miles of very cheap fibre! Also, $ stores often sell party flashlights with a similar fibre "bush" on the end. Now, purists will say that these cheap fibres are not as light transmitting as the more pure expensive kinds. Doubtless they are right, but I wonder if you could tell the difference in the short run inside an N loco or caboose [;)]

Second point "The end your talking about at the light source, do you mean glued?"

Probably not glued to the bulb, because of heat considerations, and having to unglue to change a bulb.(the glue will degrade, and often discolour, which is not what you're after [:(]
However the wretched thing has to be fixed somewhere,or it will wander off and get out of alignment. So, glue or tape the fibre so that the end just butts up aganst the bulb or LED. A tiny gap is probably best for a bulb, again because of heat. With a LED you can go right against the thing.

[der5997]

higssy: " Should the fibre optics be available at the local hobby store or am I looking at Radio Shack or something like that?" (haven't figured out how to quote in this Forum yet )

OK, your LHS should be able to get plastic fibre. However, there's a cheaper way to go. You know those table lamps that have fibre optics sprouting from them like a small bush? They were a fad some time ago. Fads end up in yard sales. Miles of very cheap fibre! Also, $ stores often sell party flashlights with a similar fibre "bush" on the end. Now, purists will say that these cheap fibres are not as light transmitting as the more pure expensive kinds. Doubtless they are right, but I wonder if you could tell the difference in the short run inside an N loco or caboose [;)]

Second point "The end your talking about at the light source, do you mean glued?"

Probably not glued to the bulb, because of heat considerations, and having to unglue to change a bulb.(the glue will degrade, and often discolour, which is not what you're after [:(]
However the wretched thing has to be fixed somewhere,or it will wander off and get out of alignment. So, glue or tape the fibre so that the end just butts up aganst the bulb or LED. A tiny gap is probably best for a bulb, again because of heat. With a LED you can go right against the thing.

[cacole]

Try All Electronics (www.allelectronics.com) for LEDs of all shapes, sizes, and colors at surplus prices. For example, a white 3mm LED (Catalog Nr. LED-83) is priced at $2.85. Radio Shack probably doesn't even have this size LED in stock, and would want nearly $5 each if they did.

[cacole]

Try All Electronics (www.allelectronics.com) for LEDs of all shapes, sizes, and colors at surplus prices. For example, a white 3mm LED (Catalog Nr. LED-83) is priced at $2.85. Radio Shack probably doesn't even have this size LED in stock, and would want nearly $5 each if they did.

[Anonymous]

Answering the debate on whether or not the light output is AC or DC.
The output signal is varying from o volts to plus (insert 10-18 volts depending on P'supply input.)
It does not go below zero volts, therefore in one sense it is varying DC voltage, and will measure as DC on a DC input to your meter. However if you measure it on an AC meter, then the waveform looks roughly like a sine wave and will measure as AC.
However the reality is that it is DC, that is if you put a LED (or diode) across it, then one end of the Diode will always have positve jolts, while the other has negative jolts. Therefore care must be taken to get the polarity right.
Note that measurements obtained on either DC or AC meters are not accurate. The DC meter is only averaging what it sees., and the AC meter is cailbrated to read sine waves, not complex waves. For the purpose of calculating resistor values for 1.5v bulbs, the best bet is to build the little experimental resistor matrix that was a recent MR mag article.
Same arguement applies to pulse controllers, the output goes from zero to plus 12-16 volts with a variable pulse width determining the energy available to drive the DC motor. Throw the reverse switch and the output is still zero to 12-16 volts, but the zero changes from the left to right rail or vice versa. Again you can measure an inaccurate DC voltage or AC voltage.

[Anonymous]

Answering the debate on whether or not the light output is AC or DC.
The output signal is varying from o volts to plus (insert 10-18 volts depending on P'supply input.)
It does not go below zero volts, therefore in one sense it is varying DC voltage, and will measure as DC on a DC input to your meter. However if you measure it on an AC meter, then the waveform looks roughly like a sine wave and will measure as AC.
However the reality is that it is DC, that is if you put a LED (or diode) across it, then one end of the Diode will always have positve jolts, while the other has negative jolts. Therefore care must be taken to get the polarity right.
Note that measurements obtained on either DC or AC meters are not accurate. The DC meter is only averaging what it sees., and the AC meter is cailbrated to read sine waves, not complex waves. For the purpose of calculating resistor values for 1.5v bulbs, the best bet is to build the little experimental resistor matrix that was a recent MR mag article.
Same arguement applies to pulse controllers, the output goes from zero to plus 12-16 volts with a variable pulse width determining the energy available to drive the DC motor. Throw the reverse switch and the output is still zero to 12-16 volts, but the zero changes from the left to right rail or vice versa. Again you can measure an inaccurate DC voltage or AC voltage.

[Anonymous]

Fibre Optics: I use a lighter to heat the tip. It will form a convex "lense". I use .040" and .060". I pick the size that is slightly smaller than the opening and heat the fibre optic with the lighter until it is of diameter to seat in the opening. The soldering iron should work also.
1k (1,000-ohm) resistors: I read an article from Railroad Model Craftsman (sorry MR) "Demistifying DCC, Part 8". It covered how to use and care for LED's and bulbs. Works perfect with no problems. I have not lost an LED yet!
Jameco: The more you order, the cheaper it is. 1 led is 2.95 ea, 10 leds are 2.65 ea...shipping is reasonable. You can pick which method you want: FedEx, USPS, UPS, air, ground....I pick the cheapest.
I also use heat shrink to keep LED light out of the cab.

[Anonymous]

Fibre Optics: I use a lighter to heat the tip. It will form a convex "lense". I use .040" and .060". I pick the size that is slightly smaller than the opening and heat the fibre optic with the lighter until it is of diameter to seat in the opening. The soldering iron should work also.
1k (1,000-ohm) resistors: I read an article from Railroad Model Craftsman (sorry MR) "Demistifying DCC, Part 8". It covered how to use and care for LED's and bulbs. Works perfect with no problems. I have not lost an LED yet!
Jameco: The more you order, the cheaper it is. 1 led is 2.95 ea, 10 leds are 2.65 ea...shipping is reasonable. You can pick which method you want: FedEx, USPS, UPS, air, ground....I pick the cheapest.
I also use heat shrink to keep LED light out of the cab.

[Anonymous]

Thanks der5997, that's very informative. Should the fibre optics be available at the local hobby store or am I looking at Radio Shack or something like that?
The end your talking about at the light source, do you mean glued?

[Anonymous]

Thanks der5997, that's very informative. Should the fibre optics be available at the local hobby store or am I looking at Radio Shack or something like that?
The end your talking about at the light source, do you mean glued?

[der5997]

higssy: Rocky doesn't seem to have answered yet about the fibre optics and lenses.

Here's my take on what he may have meant.

Hold the end of a piece of plastic fibre optic material not far from a hot soldering iron. Watch what happens. That blob of plastic that forms makes the lens. You can cut off a stem for mounting the lens if all you're after is a replacement for a jewel. Or you can thread the fibre through the opening where the light would be, pull the lens into the light fitting, and arrange the free end against the light source inside the loco.

All this assumes that you drill out the back of the light fitting on the locomotive to receive the lens and fibre, or lens and stem. If you've ever searched the floor for a fallen jewel, you'll likely appreciate the extra handle a stem provides!

[der5997]

higssy: Rocky doesn't seem to have answered yet about the fibre optics and lenses.

Here's my take on what he may have meant.

Hold the end of a piece of plastic fibre optic material not far from a hot soldering iron. Watch what happens. That blob of plastic that forms makes the lens. You can cut off a stem for mounting the lens if all you're after is a replacement for a jewel. Or you can thread the fibre through the opening where the light would be, pull the lens into the light fitting, and arrange the free end against the light source inside the loco.

All this assumes that you drill out the back of the light fitting on the locomotive to receive the lens and fibre, or lens and stem. If you've ever searched the floor for a fallen jewel, you'll likely appreciate the extra handle a stem provides!

[Anonymous]

BENT: I did a little research and found dcc controllers works with either DC or AC power supplies. I use a 16VAC MRC powerpack that came with my Prodegy DCC. That may be why my headlight is AC but yours is appears as dc if you are using a dc powerpack. I gather the decoders use "switches" to turn on-off headlight suppling track power to them. I am goint to do an experiment when I get time and swap in a filtered dc power pack and see. I am also going to note if it changes the way no-dcc locos sound.

[Anonymous]

BENT: I did a little research and found dcc controllers works with either DC or AC power supplies. I use a 16VAC MRC powerpack that came with my Prodegy DCC. That may be why my headlight is AC but yours is appears as dc if you are using a dc powerpack. I gather the decoders use "switches" to turn on-off headlight suppling track power to them. I am goint to do an experiment when I get time and swap in a filtered dc power pack and see. I am also going to note if it changes the way no-dcc locos sound.

[der5997]

flea307: Facer , a Brit expression ( how current I can't say since we left in 1967) for something that brings you up short. to be brought up short is to be stopped in one's tracks. So you see, there is a RR link in there somewhere! [:D]

[der5997]

flea307: Facer , a Brit expression ( how current I can't say since we left in 1967) for something that brings you up short. to be brought up short is to be stopped in one's tracks. So you see, there is a RR link in there somewhere! [:D]

[BentnoseWillie]

QUOTE: MRC decoders run the headlights on AC, at lead my digital VOM show its AC.

Weird. I have a couple of MRC decoders, but haven't connected lights to those ones. Maybe I should see what they have on the function outputs. My TCS, Atlas and Digitrax decoders all put out DC.

[BentnoseWillie]

QUOTE: MRC decoders run the headlights on AC, at lead my digital VOM show its AC.

Weird. I have a couple of MRC decoders, but haven't connected lights to those ones. Maybe I should see what they have on the function outputs. My TCS, Atlas and Digitrax decoders all put out DC.

[Anonymous]

MRC decoders run the headlights on AC, at lead my digital VOM show its AC. And I read " and a 1K resistor in series with both. " to read 2 resistors ie. one with the led and one with the diode. That's why LED fried at 16 volts? And another way is to power LEDs off of aaa batteries in HO. I'll still stick with light bulbs. I never have had one give problem. I follow KISS most of the time.

[Anonymous]

MRC decoders run the headlights on AC, at lead my digital VOM show its AC. And I read " and a 1K resistor in series with both. " to read 2 resistors ie. one with the led and one with the diode. That's why LED fried at 16 volts? And another way is to power LEDs off of aaa batteries in HO. I'll still stick with light bulbs. I never have had one give problem. I follow KISS most of the time.

[BentnoseWillie]

QUOTE: As for DCC only needing a 1K resistor, I disagree. My DCC shows AC voltage at the light terminal which frys LEDs.

Huh? Every decoder I've seen has DC function outputs. Using my Atlas Master system (which puts out a higher voltage to the rails than most), I get no higher than 14-16VDC on the function outputs. Haven't had a problem yet.

QUOTE: And as to using 2- 1K resistors and a diode on DC, my results showed lots of dimming at low speeds and burnouts at over 16V

I didn't say two resistors, I said one in series with both the LED and the straight diode, which are in parallel with one another. This whole circuit is then placed in parallel with the motor. Now, I've only bench-tested this, but I went to +/- 18VDC with no burnout. Dimming/dropout at starting voltage is the Achilles heel of this version, though, and I should have mentioned that. My bad.

[BentnoseWillie]

QUOTE: As for DCC only needing a 1K resistor, I disagree. My DCC shows AC voltage at the light terminal which frys LEDs.

Huh? Every decoder I've seen has DC function outputs. Using my Atlas Master system (which puts out a higher voltage to the rails than most), I get no higher than 14-16VDC on the function outputs. Haven't had a problem yet.

QUOTE: And as to using 2- 1K resistors and a diode on DC, my results showed lots of dimming at low speeds and burnouts at over 16V

I didn't say two resistors, I said one in series with both the LED and the straight diode, which are in parallel with one another. This whole circuit is then placed in parallel with the motor. Now, I've only bench-tested this, but I went to +/- 18VDC with no burnout. Dimming/dropout at starting voltage is the Achilles heel of this version, though, and I should have mentioned that. My bad.

[Anonymous]

Rocky, could you explain the use of fibre optics as lenses for you locos. It sounds interesting. I'm missing a few lenses for my Ho trains and I'm looking for an alternative.
thks

[Anonymous]

Rocky, could you explain the use of fibre optics as lenses for you locos. It sounds interesting. I'm missing a few lenses for my Ho trains and I'm looking for an alternative.
thks

[Anonymous]

Quote: "I use white LED's that I purchase from Jameco Electronics for around $2.95 each. "

Do they ship them free? I couldn't find a shipping charge quote on their site but have found that on lots of mail order stuff the shipping + parts is more than the parts locally. And if it don't work you then pay shipping back too.

As for DCC only needing a 1K resistor, I disagree. My DCC shows AC voltage at the light terminal which frys LEDs. And as to using 2- 1K resistors and a diode on DC, my results showed lots of dimming at low speeds and burnouts at over 16V.

[Anonymous]

Quote: "I use white LED's that I purchase from Jameco Electronics for around $2.95 each. "

Do they ship them free? I couldn't find a shipping charge quote on their site but have found that on lots of mail order stuff the shipping + parts is more than the parts locally. And if it don't work you then pay shipping back too.

As for DCC only needing a 1K resistor, I disagree. My DCC shows AC voltage at the light terminal which frys LEDs. And as to using 2- 1K resistors and a diode on DC, my results showed lots of dimming at low speeds and burnouts at over 16V.

[BentnoseWillie]

I use white LED's and fiber optic headlights on my engines. I get them from the local electronics supply house ($CAD 9 - ouch!) or when they have them, the Hobby shop ($CAD 2). The $9 ones are brighter, but not that much!

For DCC, a 1K resistor needs to go in line with the LED.

For DC, if the engine doesn't have a directional lighting circuit, add a diode rated for the full track voltage in parallel with the LED, in the opposite orientation to the LED (positive to negative, negative to positive), and a 1K resistor in series with both. If you don't do this, the LED will pop the first few times you reverse the engine.

If you do have a directional lighting circuit, you can dispense with the diode and possibly the resistor, depending on the output of the lighting circuit.

It's sort of a "build to suit" situation, but anyone who knows a little about electronics can help you get going, and the results are great.

[BentnoseWillie]

I use white LED's and fiber optic headlights on my engines. I get them from the local electronics supply house ($CAD 9 - ouch!) or when they have them, the Hobby shop ($CAD 2). The $9 ones are brighter, but not that much!

For DCC, a 1K resistor needs to go in line with the LED.

For DC, if the engine doesn't have a directional lighting circuit, add a diode rated for the full track voltage in parallel with the LED, in the opposite orientation to the LED (positive to negative, negative to positive), and a 1K resistor in series with both. If you don't do this, the LED will pop the first few times you reverse the engine.

If you do have a directional lighting circuit, you can dispense with the diode and possibly the resistor, depending on the output of the lighting circuit.

It's sort of a "build to suit" situation, but anyone who knows a little about electronics can help you get going, and the results are great.

[Anonymous]

I use white LED's that I purchase from Jameco Electronics for around $2.95 each. I am running DCC and use a 1k resistor to keep the voltage from burning out the led. If you are running analog (dc) you need a voltage regulator to get the voltage higher to light the LED at lower speeds. The LED's work great with DCC. The have virtually no draw, no heat and are really bright. The sometimes have a bluei***int to them, but I do not find it offensive. I am starting to use fiber optics as lenses with the LED's. The light is bright and projects well.