Lucky way to add LED h-light to 0-6-0

[on30gn15]

Hey Jonathan 
Earlier tonight, well, technically yesterday now, had an inspiration how to wire LED headlight to regular DC 0-6-0.
Had boiler shell off to get at cab roof screw when those recesses top center of frame caught my eye. They have holes. Hole go all the way through. Hmm, wonder ... could there be, in that pile of odd screws in the coupler parts tray ... ?

Turned out there was -
Have no idea what size the screws are or where they came from, but they were able to be carefully worked in to the holes in 0-6-0 frame, cutting threads as they went.
With that being a huge gamble -- some very inconvenient things could have gone wrong.


And of utmost importance, they did not meet in the middle


After a bit of brainstorming it was determined that some copper eye bolt detail parts would make good connectors. A bit of cutting and soldering later, and we have


Cut notch behind headlight mount for wires to pass through in to boiler


And now, yes now, it dawns on me that some important parts were forgotten in the photography 
Will fill in later.
3mm LED came from battery powered warm white Christmas mini light string.
And no, I haven't a clue what its ratings are.
Headlight detail was freed from boiler by careful employment of fine tooth razor saw.
Back was drilled by hand with pin vise then countersunk to fit lip of LED.
While I was at it, numberboards were drilled out too.
Also glued some steel shot inside domes.

[jonathan]

on30,

Very ingenious! I have one 0-6-0 left, DC only, with a conventional bulb.  I think I may try your technique in the near future.

Thanks for sharing.  Would love to see a photo of the finished product.

Was it hard to pull of the top mount headlight?

Regards,

Jonathan

[richg]

Typical Bachmann split chassis.
All the LED's I have ever worked with are about 20 ma max.
A 1k resistor with the LED should work. I say that because my NCE Power Cab has a red 3mm LED and 1k resistor in the connector panel that is connected directly across the DCC signal going to the track. There is no protective diode either and many users have the Power Cab and have no mentioned any LED failures. It would not be difficult to include a protective diode if you like.

Rich

[on30gn15]

Was it hard to pull of the top mount headlight?

Razor saw required, light "is one with the" smokebox. Carefully saw under housing horizontally back toward stack. Put a couple strips masking tape between lamp and stack just in case saw slips.

Wire is 30 gauge from Miniatronics.

Light housing will be glued in place after back is filled and painted.

[on30gn15]

A 1k resistor with the LED should work.

Would you believe what's being used is half that?
From a few years back have header cards from Miniatronics LED packs -->
Ultra Bright included a 560 ohm resistor for use with power supply voltages above 4.
"Yelogo" White included 270 ohm for 4-9 volts and 470 ohm for 10-16 volts.
So a 470 was used since anonymous warm white Christmas light LED was pretty much same as Miniatronics' "Yeloglo".

It would not be difficult to include a protective diode if you like.

That is something that I know about being done, but that's the end of what I know in details on it.

[jward]

Typical Bachmann split chassis.
All the LED's I have ever worked with are about 20 ma max.
A 1k resistor with the LED should work. I say that because my NCE Power Cab has a red 3mm LED and 1k resistor in the connector panel that is connected directly across the DCC signal going to the track. There is no protective diode either and many users have the Power Cab and have no mentioned any LED failures. It would not be difficult to include a protective diode if you like.

Rich

not to quibble here, but what is the protective diode for?

the led is itself a diode. i'd think it would more likely need a resistor to keep from exceeding max current.

[richg]

Typical Bachmann split chassis.
All the LED's I have ever worked with are about 20 ma max.
A 1k resistor with the LED should work. I say that because my NCE Power Cab has a red 3mm LED and 1k resistor in the connector panel that is connected directly across the DCC signal going to the track. There is no protective diode either and many users have the Power Cab and have no mentioned any LED failures. It would not be difficult to include a protective diode if you like.

Rich

not to quibble here, but what is the protective diode for?

the led is itself a diode. i'd think it would more likely need a resistor to keep from exceeding max current.
[/quote

Suppose to protect the LED from the other half cycle. That has been discussed here in the past. Photos of the arrangement have been posted here before. Some say, put the diode in series, some say in parallel. Not an issue for me. Jim Banner commented on this issue some years ago

I found the discussion in a search of the Bachmann forums.

http://www.bachmanntrains.com/home-usa/board/index.php/topic,17660.0.html
Rich

[on30gn15]

Am a rank rookie at DCC, but my brain says, wouldn't sensible decoder manufacturers have figured this in to their decoders? 

[on30gn15]

While we're at it, have a DCC ready with 8 pin socket 2-10-2 by IHC: while at this and another LED h/l job, cut off the 2-10-2's apparently 12v rated "dim bulb" incandescent headlight bulb and after 20 minutes of playing with LED and resistors there was no "let there be light" moment.

Even hooked an un-resisted LED to the wires and nope, nothing, no light, no blowout.

Am baffled as to why a 12v light bulb works on the circuit but a 1.5V LED stays dark no matter which pole is attached where.

Y'all have any ideas?

thanks again
Forrest

[richg]

Am a rank rookie at DCC, but my brain says, wouldn't sensible decoder manufacturers have figured this in to their decoders? 

Pay attention, the circuit has nothing to do with a decoder. Decoders send 12 VDC to an LED or light bub.
What I showed is the LED used to indicate that a track has DCC applied to it.

Rich

[richg]

While we're at it, have a DCC ready with 8 pin socket 2-10-2 by IHC: while at this and another LED h/l job, cut off the 2-10-2's apparently 12v rated "dim bulb" incandescent headlight bulb and after 20 minutes of playing with LED and resistors there was no "let there be light" moment.

Even hooked an un-resisted LED to the wires and nope, nothing, no light, no blowout.

Am baffled as to why a 12v light bulb works on the circuit but a 1.5V LED stays dark no matter which pole is attached where.

Y'all have any ideas?

thanks again
Forrest

Getting away from the subject at hand, You would have been better to start another discussion. Easier to track.

LED's require at least two to three volts to light and then with a 1 k resistor. LED's are polarity sensitive. Wrong polarity and they do not light. Switch the two leads.

There is a possibility the LED blew out and you did not see it happen or you had the wrong polarity with no resistor.
Generally an LED will give a loud pop if connected to 12 VDC and no resistor.

Rich

[on30gn15]

There is a possibility the LED blew out and you did not see it happen or you had the wrong polarity with no resistor.

Actually, it is now the LED working just fine in 0-6-0.

Good idea, will make a new thread.