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Lighting Only Decoder?

Wobblinwheel

By Wobblinwheel
in Hornby DCC

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Wobblinwheel Mentor

Wobblinwheel

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I have a Hornby A4 "Golden Eagle" which has it's decoder located in the tender. I am wanting to install lighting in the firebox for the "firebox flicker". I know the obvious method would be to run two additional wires from the tender decoder to the LED or bulb in the firebox. I was thinking it sure would be nice if they made a simple "lighting only" decoder I could mount in the boiler for the lighting effects. No extra wires to the tender necessary.. Anybody heard of such a decoder? One would think such a decoder would be considerably cheaper than regular decoders, and smaller too, and, depending on the amount of lights installed in the loco, would eliminate the need for all the wires going back to the tender. Wouldn't that be a good idea, since they're putting the decoders in the tender nowadays, and NOT providing the extra wires in the harness for lighting?

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Howbi Grand Master

Howbi

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Lighting (Function) only decoders are, for some strange reason, more expensive than normal decoders. But you can wire in a flickering LED with resistor to the loco pickups anyway but this would be on continuously otherwise use an ordinary inexpensive decoder given the same address as the loco.......in the UK I would use a Hattons £10 decoder........HB

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Guest Chrissaf

Chrissaf

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HB is 100% correct. For some inexplicable reason, 'function only' decoders are more expensive than normal motor control decoders. Significantly more expensive.

.

But note this: if you use a normal decoder just for the functions there is a 90% probability that it will need a motor load attached to it before it will accept the configuration of CV's. So plug it into a loco first and configure it all up before wiring it in its final resting place into the loco boiler. Some more expensive decoders include a function with a configurable CV to simulate 'firebox' flicker. To get the best effect out of the work involved in fitting the firebox LED, it may be worthwhile searching for a 'firebox' compatible decoder.

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Wobblinwheel Mentor

Wobblinwheel

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It really would be nice if the plug/harness between engine and tender had a few extra wires for lighting. I do believe my loco only has four. Two for track pickups, two for motor control. Of course, it's "no big deal" to run a multitude of extra wires from the tender to the loco, but I'd like to avoid it, if possible.... Sometimes it might be necessary to disconnect the tender from the loco, and I would hate to have to install an extra plug and socket, which could very likely be difficult to conceal. A separate decoder in the boiler would be a lot less work.... and not be so "busy".

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96RAF Grand Master

96RAF

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@wobbly

Go to your local cheap shop and look for those flickering battery operated tea lights. You normally get quite a lot of them for little money.

You can then tear them apart for the leds. I use my standard 1K ohm resistor. They are usually amber and you can strap a red led into the circuit to provide a varied effect.

Rob

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Wobblinwheel Mentor

Wobblinwheel

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@wobbly

Go to your local cheap shop and look for those flickering battery operated tea lights. You normally get quite a lot of them for little money.

You can then tear them apart for the leds. I use my standard 1K ohm resistor. They are usually amber and you can strap a red led into the circuit to provide a varied effect.

Rob

That sounds like the ticket... I already have the tea lights! (Why, I don't know...) Thanks!

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choralc Mentor

choralc

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As soon as I read out RAF's last message the good lady dashed out of her chair and as I began to read Wobbly's reply she called out that she couldn't hear me as she was hanging upside down in another room and promptly reappeared with a flickering tea light.

 

So Wobbly I didn't know I had these either until a moment ago. She's keen to get my hammer now to open it up.

 

With DCC which LED terminal should the resistor go on if I connect it up to the pickup wires for always on?

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96RAF Grand Master

96RAF

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I have got steady glow buffer leds and flashing rear leds on guards vans powered direct from DCC rail pickups using a 1K ohm resistor without problem so far.

 

I lashed up the flickering tea lights to see if they would look OK as gas platform and street lights on DC but never incorporated them.

Rob

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RB51 Grand Master

RB51

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I would think the effect would look OK especially at 3V - but are they IMHO too big for OO. The LED in one I have just opened (I was surprised to find them in the bits box) is c. 9mm. R-

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morairamike Mentor

morairamike

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 While on the subject of using tea lights I have used them in four other applications.

First, is a builder's site rubbish fire, the tea light lLED was removed from the case and glued into the base board. The fire was built up around it, match sticks for joists etc. (this is a N gauge layout at club), a dab of red paint on the bulb to give red as well as pink colur. The unit has a remote switch and runs off its original 3V battery but could be hard wired if required to 12V with resistor. A bit of cotton wool for the smoke.

Second, is as a trigger for a welding arc light, this time in my 00 gauge engine shed inspection pit. This I run off a switched 12V supply using required resistor. The original tea light bulb is in series with a bright white LED. The bright LED switches on and off when the tea light flickers. Looks pretty realistic.

Third (2 of), are used as the flame of a gas burner in a hot air balloon (again on the N guage layout at club). The tea light base unit, suitably modified, is fitted inside (in one case) a small teddy bear  to represent Pudsey. The battery is inside him and when switched on it looks like the flames for the hot air gas burner. The other is stress relieving rubber ball with a company logo on it. Again the unit is inside with external switch. Hot air balloons these days are all shapes and sizes.

Fourth, is as candle effect inside my Metcalf church. Could also be used as fire effect in a house or a group could be used to represent a house or other building on fire

There's no limit of the uses for these cheap items from the £ shop 4 or sometimes 6 for a £1.

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Guest Chrissaf

Chrissaf

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Yes HB, that could have a bearing on how the flicker circuit works. With a single diode rectifier, the DC output is pulsed with gaps between the pulses. Albeit at DCC frequencies, these gaps will be very small indeed. A bridge rectifier goes some way to filling in these gaps with additional positive voltage, thus making the DC output flatter.

.

For clarity, are you saying that you tried it with a single diode (half wave rectification) and it didn't work ?

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Howbi Grand Master

Howbi

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In the full B.R circuit just tried a red LED in series with the yellow flicker LED and it flickers in sympathy.......creates a very nice fire effect especially when the bulbs are wrapped in a bit of crinkled tin foil (carefully to avoid a short).

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