Fitting LEDs to 4mm scale signals

[Captain Kernow]

I am probably going to make a start on the running signals for Callow Lane soon. They will be built from MSE and Alan Gibson components.

 

Like my previous layouts, these signals will be built as working models, using some kind of motor (probably Hoffman point motors).

 

Unlike my previous layouts, I plan to illuminate these signals, using some small LEDs I've already bought. The idea is to wire them up into the structure of the signal. This bit is not the problem, but the purpose of this request for information concerns how to disguise the LED as a signal lamp on the post?

 

I had thoughts of moulding Milliput around the LED, but I'm not sure how easy or effective this will be.

 

Is it practical to drill out a whitemetal signal lamp and glue the LED in there?

 

How have other people achieved this - I'd be grateful for your suggestions.

 

Many thanks.

[Softvark]

I've not done this in 4mm but I have in 7mm using whitemetal lamps.

 

I drilled the lamp through the lens into the body and then drilled upwards from the base until it met the horizontal bore. I used an SMT LED and soldered very fine enamel wires to it. I passed this into the lamp through the base hole until the LED appeared in the lens hold. It was glued in place with super glue and when dry the base was filled with Milliput. I then over filled the lens hole with Carrs Liquid Glass so it formed a slight dome which the red LED shone through very clearly.

 

It works very well and I've now made several. The only problem is the liquid glass dries clear but I guess you could put a very thin coat of red acrylic over it which will still allow the light to shine through.

 

I'll try and take a photo to post later.

 

Julian

[Peter Beckett]

On my 4mm working semaphores, I had some old Ratio kits so I cut the lamps of the Ratio dolls, drilled out holes for the globe/led and glued the lamps to the dolls on my signals. Works great and is scale size as well. All I had to do then was paint them black to stop the light showing through the white plastic.

 

Peter

[Gwiwer]

No issues with paint, plastic or filler overheating?

[Peter Beckett]

On my originals I used the 3v 1mm diameter globes with a 1k ohm resistor fed by 12v DC and had it on for over 8 hrs with no ill effects. After talking to Richard J at DCC Concepts the next batch will have some of his LED's which will be even better

 

Peter

[96701]

Somebody else on a separate thread pointed the way here

[Brinkly]

Will you keep us up to date on this 'mini project' please Tim as it sounds rather interesting. Didn't one of the RMWeb challenge layouts from a few years ago have ground signals with LEDs?

 

Regards,

 

Nick.

 

 

[beast66606]

Hi C.K,

 

Personally I don't like LEDs in semaphores, oil lit lamps were incredibly dull and difficult to see and I think LEDs are too powerful for this period - but I know others use them (which is their choice and I respect that)

[Brinkly]

Hi C.K,

 

Personally I don't like LEDs in semaphores, oil lit lamps were incredibly dull and difficult to see and I think LEDs are too powerful for this period - but I know others use them (which is their choice and I respect that)

 

Would resistors not dim the light enough?

Regards,

 

Nick

 

 

 

[beast66606]

Would resistors not dim the light enough?

Regards,

 

Nick

 

Not in my humble one - resistors on LEDs are not a sliding scale like a lamp, they dim a bit and then go out - but each to their own of course.

[Brinkly]

Not in my humble one - resistors on LEDs are not a sliding scale like a lamp, they dim a bit and then go out - but each to their own of course.

 

Just wondered! When I taught a unit on circuits last term to a year 5/6 class we had a 6v bulb with 1/2v going through it and it was very dim! But like you said it's personal choice at the end of the day. (Would look good in a dim room though! )

 

Regards,

 

Nick

[Captain Kernow]

Somebody else on a separate thread pointed the way here

Thanks for the link - these look rather promising...

 

Personally I don't like LEDs in semaphores, oil lit lamps were incredibly dull and difficult to see and I think LEDs are too powerful for this period - but I know others use them (which is their choice and I respect that)

I will admit to not having really thought much about the brightness - so are you recommending that it would be better not to illuminate the signals at all, Dave? Or is there an alternative to the LED that would do the job? (what about these Nano thingeys in the above link?).

[meple]

Not in my humble one - resistors on LEDs are not a sliding scale like a lamp, they dim a bit and then go out - but each to their own of course.

 

 

Drive them with a PWM circuit - that gives controllable dimness (if there is such a word).

 

 

[beast66606]

Thanks for the link - these look rather promising...

 

 

I will admit to not having really thought much about the brightness - so are you recommending that it would be better not to illuminate the signals at all, Dave? Or is there an alternative to the LED that would do the job? (what about these Nano thingeys in the above link?).

 

Lamps ? - little ones ?

[Captain Kernow]

Lamps ? - little ones ?

Right - didn't realise there was any conventional bulb small enough to fit inside a 4mm lamp housing?

[beast66606]

Right - didn't realise there was any conventional bulb small enough to fit inside a 4mm lamp housing?

 

Hi CK,

 

I'm afraid I'm a classic case of not liking the solution but no real alternative, the circuit suggested might make LEDs more usable ? Give them a trial, you might like them. Maybe a small LED painted with some LED paint might be dull enough ? - needs some experimenting.

[Captain Kernow]

OK, fair enough - I might look at these nanobots a bit closer, but I'll probably try one of the LEDs that I already have in one of the signals. Thanks for everyone's comments!

[Tim V]

Personally, I don't bother lighting the signals, most of the time they weren't lit anyway. The sectional appendix says when the lamps were lit.

 

And I don't operate my layout at night time.

[Peter Beckett]

Which is why I fitted the 3v globes because I can dim them to emulate oil lamps. I bought them from here http://www.timesaverlayouts.com/leds.html but you should be able to get them in UK

 

Peter

[-missy-]

Hello

 

From my experience fitting LEDs to 2mm scale signals I have found them to be more than adequate for the purpose. I use warm white surface mount LEDs from HERE and fit them with a variable resistor (under the baseboard) so I can tweak the brightness of them. To get a pin point of light I stick a bit of half round plastic over the front of the LED with a small (0.5mm) hole drilled through it and them paint the whole thing black. There is a bit more detail and pictures on my blog if anyone wants to take a peek.

 

Missy

[Captain Kernow]

Personally, I don't bother lighting the signals, most of the time they weren't lit anyway. The sectional appendix says when the lamps were lit.

 

And I don't operate my layout at night time.

Actually, Tim makes a stonkingly valid point here - it is more than likely that this out-of-the-way goods yard wouldn't have had the signals lit, let alone operate during the hours of darkness, although I suppose some operation might have been possible after dark during winter.

 

Still not decided whether to fit lamps or not, but I kind of want to do at least one signal, if only to prove that I've done it!

[Pugsley]

I use warm white surface mount LEDs from HERE

I've bought LEDs from them as well, they provide very good service and I had my order within a couple of days - pretty good for shipping from Germany!

[Adrian Wintle]

The Miniatronics LEDs are approximately the same size as lamps. With the blob filed down and the body painted I've used these as tail lamps on coaches. The the upper lead can be bent to resemble a handle.

 

Adrian

[beast66606]

Actually, Tim makes a stonkingly valid point here - it is more than likely that this out-of-the-way goods yard wouldn't have had the signals lit, let alone operate during the hours of darkness, although I suppose some operation might have been possible after dark during winter.

 

Still not decided whether to fit lamps or not, but I kind of want to do at least one signal, if only to prove that I've done it!

 

I suspect that most running line signals would be lit from sunset until at least close of traffic and then extinguished until the line reopened again the following morning (unless its a Sunday!) until sunrise, I think the SA lists the exceptions rather than the norm, semaphore signals controlling exit to the main lines were probably also lit at the same times. I'm afraid my SAs are mostly LNWR/LMS/BR LMR.

 

Give one a go - remember you can get LED paint, yellow for example will take the brightness out of of yellow/white/sunny white LED.

[Tim V]

When the lamps were lit, they were on all the time. The lamp would usually last about eight days. The lampman/porter would have to go out to collect them once a week, with replacement lamps.

 

They were not extinguished on a daily basis.