DIY loco lights using fibre optics and LEDs

[NeMo]

Hello all,

Apropos to this eBay sale for 3 mm LEDs and lengths of 1 mm fibre optic.

I was given a Farish Class 50 for my birthday yesterday; I know it isn't considered a particularly detailed model, but I think adding a headlight could be a fun project. Not having a clue about how to do this though, I was wondering if anyone has any advice. I'm thinking about drilling a 1 mm hole, threading a fibre optic into the hole, then connecting the other end to an LED. There's certainly plenty of space inside the model's body!

I'm assuming since LEDs are diodes, they would only light up in the direction of travel.

Do-able? Will I need any resistors? What might I do to make the headlight a better size if the diameter of the 1 mm fibre optic is too thin?

Cheers, NeMo

[scotsoft]

If you have space you could fit a bridge rectifier which will let the LED work in both directions.

If you are going to power it from the wheels then you will need a resistor.

If the 1mm fibre optic is too small, you could apply heat to the end of the fibre which will form it into a ball which will make it bigger.

cheers John.

[Sprintex]

1mm fibre should be fine as that's a scale 6" light, wouldn't have thought they'd be much bigger than that

I presume you're using DC control? If so then yes it will only work in one direction which is what you'd want anyway for a headlight


Paul

[NeMo]

Thanks guys; very helpful. I'll e-mail the vendor to find out if these work on 12 V DC or need a resistor. Nothing said about this in the advertisement, but who knows?

Cheers, NeMo

[upnick]

I'd be  going down the SMD route for lights  you can mount them   directy   to  the  loco   body  being so small  a lot more secure fixing finding  space for a 3mm   LED   &  fibreoptics so they are  in place is   a pain  & you'll  need to  make sure  you   sort the  body for lightbleed

All   LED's  /SMD's     need a resistor  inline on the postive side

[NeMo]

Quite right; thank you.

This from the vendor: "LEDs do need a resistor as their normal voltages are red 2v, white 3.5v. I do send resistors free(1 per LED) with all my LEDs so they will be okay for use at 12v-18v DC"

Cheers, Neale

All   LED's  /SMD's     need a resistor  inline on the postivie side

[upnick]

Quite right; thank you.

This from the vendor: "LEDs do need a resistor as their normal voltages are red 2v, white 3.5v. I do send resistors free(1 per LED) with all my LEDs so they will be okay for use at 12v-18v DC"

Cheers, Neale

If these are the free  resistors that i've had  in the past  bin them   if they're a  bright blue   resistors they are cheap   &   nasty on  12V  they  get very hot very quickly.

Resistors are cheap  to buy  but  get the right ones  these for a  start are ideal,  the company here are  always  very quick  &   carry good stocks (no connection just a very satisfied customer) 

http://www.ebay.co.uk/itm/50-x-1K-Ohm-Carbon-Resistor-1k-Resistors-1-4W-/300540514294?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item45f99c4ff6

[NeMo]

We shall see! Have ordered some: for a fiver, worth a flutter. Could be a fun way to make the Farish 50 a little more entertaining (note: I didn't say 'a better model').

Cheers, Neale

[NeMo]

See below for a video of the little LED in action. Nothing terribly clever involved; soldered resistor in place, put insulating tape around bits to stop light leaking out, snapped off little plastic fake light from nose, and threaded through fibre optic and cut to right length.

Cheers, NeMo

[smg id=6156 type=av]

[Newportnobby]

Looks very effective - well done

[47033]

Nice job, it does look good.