LED lighting

[Stuart Badger]

Hi PDs - I need some advice and a quick course of instruction! I THINK I understand electricity (pre 1950) but electronics is the science of satan as far as I'm concerned.

I want to light my model of the Connaught (cabins, portholes etc - she didn't carry any navigation or running lights as there was no legal requirment then!). I was thinking of using these new fangled LEDs, yellow ones to give that gaslight glow.

What I need to know is in PRACTICAL terms how does one wire them? in series or parallel? are they just connected to a battery, do they require any electronic wizadery, do they come in different voltages etc.

Any help will be gratefully received!

Stuart

[towboatjoe]

I just wire mine up parallel on a 3 volt source. LEDs are polarized so you have to have + to + and - to -. If they're backwards they won't work.

[Eddy Matthews]

LED's do come in different voltages, as well as different light outputs (Lumens), and as Joe pointed out, they are polarity sensitive - You won't do any harm if you connect them the wrong way, they simply won't work!

Buying all the LED's seperately can be expensive, but if you take a look at places such as "Poundland" in the UK, they do LED light units used for camping at only £1 each, You could either install the complete unit as it comes, or dismantle them for the components. The slight downside is that they are white LED's, but a bit of amber headlight paint will give you the colour you require....

http://www.poundland.co.uk/pages/offers/camping.aspx

Regards
Eddy

[Eddy Matthews]

Just to clarify a little (or confuse more?), When I said you can get LED's in different voltages, that isn't true strictly speaking, the higher voltage ones actually have a built in resistor to accept the higher voltage.

All LED's actually operate on between 1.5v - 3v depending on their colour. Various colours need different voltages....

Assuming the colour you have chosen needs 2v to work at full intensity, you can wire up 6 in series and connect them to a 12v battery exactly as you would with normal light bulbs. Applying too much voltage will burn them out quicker than usual, and too little voltage and they won't light at all.

So did I help or confuse?

Eddy

[Stuart Badger]

That's brilliant lads -

Towboat and Eddy. Thanks very much. I think I shall wire them in series groups to operate off the same battery as the motor. I would love to power the model with steam - but it will simply be too difficult to arrange enough access.

thanks again.

Stuart

[towboatjoe]

Be sure to wire them up series/ parellel. If you run them in series it will weaken the intensity of the LED. May not even work at all plus when one goes out they all go out.

[mjt60a]

if you want to read a lot of technical stuff, have a look at this page - http://www.starshipmodeler.com/tech/mh_led.htm
I got my LEDs from here - http://stores.shop.ebay.co.uk/Goodwill-Leds-Sales - you get resistors that can be connected in series so each can run off 12 volts (probably with model rail enthusiasts in mind) but I have also connected two in parallel to run on 6 volts without problems... that said, they have to be the same type or the voltage will not be distributed correctly, I tried to do that with a green and a red (for navigation lights) and the red one became so hot it melted the solder - turns out the max voltage for a red LED is 2.5 volts, 3.4 volts for a green or white (at least it was with the ones I had) also, the 5mm dia LEDs take a higher current than 3mm ones so they can't be used together in series circuits... (the supplied resistors - from 'goodwill sales' - are different for each type)

by the way, october 2009 issue of Model Boats has an article about using LEDs apparently ...and I'm sure I recently read one, possible in Marine Modelling a month or two  ago...

[Stuart Badger]

Thanks for that - I shall begin some reading I think!

Stuart

[big-geoff]

I have found a good source for led's is my local garden centre at xmas.

They always sell a set of 5 white 5mm led's attached to a 2 cell AA battery pack, they have a good intensity and are just right for navigation lights, you have to colour the red & green with a bit of paint.

The wires are a bit thick but nothing that cannot be replaced and extended to suit your need, the five lights make the 2 mast lights, port/stbd and stern light, weight is not significant and they have a battery box & switch already fitted.

Last year I bought out their stock and got a thick ear from the missus, worth the pain.

Price between £2.99 and £4.99 depending on the greed of the seller.

Watch out for the flashing units as well, could be good for a disco boat.

TTFN

Geoff

[mjt60a]

....for navigation lights, you have to colour the red & green with a bit of paint....

The best thing (i've found) for that is the coloured lacquer for making fake stained glass windows, most B&Q, Homebase etc. places have it... it may even be possible to mix a colour to create the 'golden glow' effect of grain-of-wheat lamps from the rather blue-ish glow of 'white' leds - but I haven't tried it yet 

[Stuart Badger]

Thanks for the tips guys. I may well purchase a set of xmas lights here and 'pull them apart. The tranparent laquer for 'stained glass' painting is available here!!!!

Stuart

[Talisman]

Hi
while wasting some time today i noticed there is an article in Model boats this month about LEDs

When i bought my last lot of LEDs i bought them from a Ebay seller in Hong Kong and they worked out at about 20p each if i remember right - sorry can't remember the sellers name.

anyway one of the links from the magazine is for a supplier that moulds the LEDs into lights (if that makes sense)

Might be of interest to Eddy if your still looking for deck flood lights.

http://mysite.verizon.net/res1tf1s/id12.html



http://www.modelbouwshopnederland.nl/?menu=category&categoryID=442292

(If it helps i used google to do the translation of the sites)

[Talisman]

Just had a rumage at the bench and still have loads left and the appropriate resistors if you need a few let me know.
They are the small domed type - white/clear 3mm
Kim

[cosmic]

Stuart, cosmic here. Sorry to chime in so late on this thread, I just got back here after a long absence. Go here http://led.linear1.org/led.wiz for a good calculator that will give you a wiring diagram for any LED array you want. All you need to know is the forward voltage and current of your LED(s). Also, if you might want them to flicker, you can look at my tutorial on the MSW database.

[Spankbucket]

Like Big-Geoff says look in retailers around Xmas.

A couple of years back Homebase were selling 24 white Leds attached to a switchable battery case for miniature Xmas trees. I bought a bagful as they were only £4.99 each and have used them successfully in model theatres.

To mount the bulbs I used strips of 5mm foamcore drilled with suitably spaced holes (6mm I think) and just pressed the bulbs in. The only restriction is that he bulbs are at fixed centres on the cable (around 5 cm I think).

I have one left and will try it on my current boat project when I get near the upper deck stage.