12 v LED lights, red or white

[Matty F]

I can't see what I want so I suppose I'll have to cobble up something. I want basically a ball of LEDs that radiate light in all directions, half of them red and half white (or yellow). I'll switch on the different colour s separately. And I want a diffuser over them so they don't look like a pil e of LEDs. If it looked like an oil lamp that would be ideal. No I don't wa nt an oil lamp as it takes too long to change colours.

I could get a lot of LEDs and wire them up 4, 5 or 6 at a time to the 12 vo lts. Or each LED could have its own resistor, but that seems wasteful, and will flatten the battery after a few hours. I don't really care if some LED s are brighter than others, as long as they don't burn out.

The shops that I will be buying the individual LEDs from will have no idea what type they are or what voltage they need. I suppose I'll have to experi ment.

I see LED strip lights are quite cheap. I could roll them up and make a bal l. Do they have resistors? I think not.

Also if I could get a 12v generator that runs off steam at 120 psi that wou ld be good too! But that's for another day.

[Adam Aglionby]

f of them red and half white (or yellow). I'll switch on the different colo urs separately. And I want a diffuser over them so they don't look like a p ile of LEDs.

Baking parchment/ grease proof paper can be a suprisingly good diffuser or oyur local theatre supplier for a riffle through the gel books.

If it looked like an oil lamp that would be ideal. No I don't want an oil l amp as it takes too long to change colours.

volts. Or each LED could have its own resistor, but that seems wasteful, an d will flatten the battery after a few hours. I don't really care if some L EDs are brighter than others, as long as they don't burn out.

Typically 3 white , blue & true green LEDs in series with resistor on 12V r ed, amber, yellow green 4 or 5 in series or bigger resistor ;-)

a what type they are or what voltage they need. I suppose I'll have to expe riment.

all. Do they have resistors? I think not.

Usually do , rolling them round a cylinder in a spiral or as sides a polygo n might be neater,.

ould be good too! But that's for another day.

miniature turbine running an alternator...

[meow2222]

f of them red and half white (or yellow). I'll switch on the different colo urs separately. And I want a diffuser over them so they don't look like a p ile of LEDs. If it looked like an oil lamp that would be ideal. No I don't want an oil lamp as it takes too long to change colours.

volts. Or each LED could have its own resistor, but that seems wasteful, an d

very

EDs are brighter than others, as long as they don't burn out.

a what type they are or what voltage they need. I suppose I'll have to expe riment.

you need to get ultrabrights. Indicator LEDs put very little light out

all. Do they have resistors? I think not.

99p shop ones dont. ISTR they had red & white strings

ould be good too! But that's for another day.

120psi is rather beyond a lego engine.

NT

[alan]

Colour changing LED bulb pointing upwards into a round diffuser. It will come with a remote to allow only red or only white

Also check white and red LEDS (12V) that are sold as replacement bulbs for cars

Note: Ebay links are for reference only and not a recommendation for the product or seller.

[The Natural Philosopher]

mamod steam engine natch!

[Matty F]

This is the effect I want, but the light being switchable between red and white.

[alan]

Cannibalise a colour change floodlight. The single LED is fixed to a heat-sink (the metal case) with 2 screws.

I've seen similar warnings about some of the China made white floodlights but the couple I've taken apart were much better made and the earth was connected to the metalwork. The mains to 12V(?) converters were also a much larger than shown in the video and were fully potted.

How large are you going to make your unit and what wattage? When you start getting to 1W or more serious consideration should be given to heat-sinks.

[Dave Liquorice]

Is the white supposed to be bright enough to illuminate the track so you can see the sheep on the line 50 yds ahead or just an "I'm coming towards you" indication?

I can't see whats wrong with a white light source of some sort and a circular frame with a red gel in it that you just drop into a holder in front of the luminaire (or put behind the hinged glass cover?). OK you'll have to get of your bum not just flip a switch but ...

Personally I think multiple sources and some diffusion won't look right.

[Robin]

If you only need a couple of Watts for LEDs then perhaps a thermoelectric generator into a backup battery? I've not played with one since 1975 but see they are commercially available if you (exceptionally!) don't want to build your own from scratch.

[Matty F]

It would be nice to illuminate the track but not really necessary as there are street lights.

That's precisely what the picture shows. So somebody has to climb down and run around to the other end, climb up in the dark and put the gel in place, and run back to put some more coal in, making sure the flames don't reach and burn the gel. Meantime somebody else has to lock the controls at one en d and race to the other end. And do this every few minutes. So it's about m inimising the number of things to be done. It's easier to throw a switch.

[Martin Brown]

One solution suitable for oil lamps is a nominal 2W corn on the cob type halogen replacement bulb. Like this one and have one red filtered.

You can't make them for less.

The other alternative if you can provide heat sinking would be something like this from Rapid

And a deep red filter to insert in front of it.

I have a real sens of deja vu about this question.

[John Rumm]

They look small enough that you could mount two - one with a gel filter round it and one bare, then just switch between them.

[Brian Gaff]

So you will no doubt need a very fast computer to emulate the variation of the colours to look like an Oil lamp.

Sounds like something a vintage steam exhibition might have already built. I wonder who supplies those places?

Brian

[meow2222]

What's currently stopping you?

NT

[Matty F]

I saw some of those yesterday. They would be ideal except that I suspect they won't put out enough light, or if they do, will cost more than I'm willing to pay for myself. Maybe I'll go back to the 15 watt incandescents until the oil lamps are made.

After lights have been pushed through a brick wall they may need some adjustment, or maybe a complete redesign!

[Martin Brown]

If you speak in riddles it is impossible to offer relevant advice.

[Matty F]

Well I don't really want to say in writing what happened, but I imagine the headlamp on this needs a rebuild:

[Nightjar]

You need a longer bit of track, so you don't have to change direction so often.

Colin Bignell

[Gazz]

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Couldnt you make something up using a solenoid or servo that moves the red filter at the flick of a switch? or even something purely mechanical, bowden cables to pull the red lens into position one end, whilst removing it at the other, could even connect it to the reversing lever to make it automatic?

[John Williamson]

Or join the ends up so you have a continuous loop. ;-)