Model Railway Forum

I have several Hornby Brake vans which have box which can have bulb put into it and there is a red lens built into rear panel of van. My question is can I put a small battery box for button cell (have seen them on ebay) and run a LED from it and push it up hole behind the rear light lens on the back.
Now when you all have stopped laughing I have never fitting LED anything in my life I just want something which glows if possible. I have noticed that a lot of these LEDs seem to be very bright...................John

Yes you can. I would rather use a coin cell either 2032 or 2025 both commonly available from supermarkets etc. Make sure they are Lithium 3V and not Alkaline(1.5V). Get a coin cell holder appropriate to whichever cell you have chosen, l would go for one that can be soldered to strip board. I would also obtain a small SPST switch which can also be soldered to strip board this will enable you to switch it on/off. Mount both switch and cell holder on strip board along with a 100R resistor as a starting point (increase resistance if the LED is too bright). With any luck you may be able to mount the LED on the strip board and align it with your hole otherwise use flying leads. You will need to observe polarity on the LED, the longer lead being Anode(+) and the shorter lead Cathode(-), the resistor can be connected to either and the appropriate pin on the cell holder.

Richard

I think you can buy kits to do this John complete with battery holder etc.

I converted a couple of mine but with rectifier circuit and wheel pick ups to run from DCC track, though if memory serves me correct you are not DCC.

Try this John, https://www.youtube.com/watch?v=bIUZ67lkkUc

The button cell is 3 volt and I would have added a 220R series resistor into one lead of the LED to reduce current to around 5 milliamp! For a slightly higher current / brighter LED use a 100R or 150R resistor.
He says he uses a flickering red 5mm LED which normally are rated at 1.8 to 2.2 volts. Therefore the battery as wired is actually over volting the LED and the LED will draw its maximum current, thereby shorting the life of the battery considerably!

teedoubleudee wrote: ↑Mon Jan 07, 2019 1:38 pm I think you can buy kits to do this John complete with battery holder etc.

I converted a couple of mine but with rectifier circuit and wheel pick ups to run from DCC track, though if memory serves me correct you are not DCC.

Yes I am sure I have seen them on the bay Terry, but I searched for ages this afternoon and found nothing. I will follow the instructions given by everybody.. Happy new year..............john

Not eBay but I think this is what you are after.

http://www.train-tech.com/index.php/lig ... h-lighting

Use a reed switch instead of a single pole then wave a neo magnet wand over it to switch it on and of

Hello Shroomy have not heard from you for ages. Nice to hear from you again. Have taken note of the reed switch idea will keep that in mind. Thanks ................John

That's a Latching reed switch. Normal ones will revert immediately the magnet in moved away. Latching reed switches are becoming harder to find foir some reason?