Mk3 Coaches lighting Tutorial

[GMD]

Richard from This Way Works has an excellent tutorial on adding lighting to Mk3s, now on YouTube. Well worth a watch. 

 

[Rallymatt]

More great work by Richard at TWW. Nice that he has shared how to make a bridge rectifier too, pennies from components. 

[ntpntpntp]

I think he gets his anodes and cathodes mixed up at one point but I know what he means 🙂   I often create my own bridge rectifiers if I can't be bothered to source the little 4 pin package.    I'd probably fit axle spring pickups rather than brass or phosphor bronze strip, or best of all live bearing cups on one side for minimum drag. 

[Postman On The Rails]

Good video something to aim for

[Too Tall]

Great video.

TBH you can pick up bridge rectifiers pretty easily and cheaply on ebay, I found "1A DIL Bridge Rectifiers 200V" pack of 10 for £3.80 with free delivery, so likely the route I would go once I work out which leg(s) the caps and resistors need to be soldered too !

I am guessing resistor on any input leg, cap across the outputs ?

Edited March 5 by Too Tall

[Fishmanoz]

I’d have thought cap across the outputs with correct polarity and resistor in series with either output?  Check by googling a bridge rectifier schematic to confirm polarity  

That drops the output voltage to around the nominal 12V for the LEDs (especially for DCC track power which is above 12V) and increases the cap discharge time giving the fade-out when power removed. Or more correctly, reduces the current draw and brightness. 

[Daedalus]

No, do not put the resistor on an input leg.  It wants to be on the output. The circuit diagram he shows is not what he builds. He's right he doesn't know much about electronics. He says you'd be OK at 16V. The leds wouldn't last long, they are 12 V strips, you could expect minimum 1.2 V drop across the bridge so the max voltage is 13.2 if you want the leds to last.

[Too Tall]

Ok, resistor on output, thanks 👍

But if the led strip used has 6 to 8 leds per coach length strip (I am assuming these strips are wired in parallel ?) then is the resistor value correct ?

[Richard-358946]

Here is the ammended diagram. It does not matter if the 1/4W 510 ohm resistor is on the negative or positive side of the LED. The resistor needs to go after the rectifier though.. the resistor is to slow the current to the led from the capacitor, 

You generally get a 0.6v voltage drop over silicon diodes.. theres two in the rectifier so assume the volt drop here is 1.2v.. no one really cares though. That 510ohm resistor can be 510ohm or go to 1k and the LEDs will actually start to dim on a 12v and 17v track. 

Out of all the components you may want a bigger capacitor or just more of the same 220uf in parallel would work well. The lights will stay on longer with more capacitance. The fade will take longer and overall brightness will be less the higher the resistor value is.. 

Ive actually made these and theres always a better way to make something, you can get a Bridge rectifier chip for example but most people have diodes kicking about vs specific components

Any questions ask away, here is the ammended schematic..

[Daedalus]

Quote

12 hours ago, Too Tall said:

Ok, resistor on output, thanks 👍

But if the led strip used has 6 to 8 leds per coach length strip (I am assuming these strips are wired in parallel ?) then is the resistor value correct ?

 

The strios are in 3 Led per segment ( 8 Cob led ). The value of the resistor is not critical, If you used 9 Led they would be dimmer. If you increse the resistor value the Leds would be dimmer if you lower it brighter, within reason. You could experiment to get the brightness you want. I don't know why he uses a 510 ohm as it is not a preferred value so less common and more costly. The nearest preferred values are 470 ohm ( brighter ) and 560 ohm ( dimmer ).

Edited March 6 by Daedalus

[Richard-358946]

Anyone fancy improving the wiring diagram but improving it to make it simpler for us mere mortals? If possible? Would love to see what you guys can come up with, could you maybe use a 7805 after a full bridge rectifier? Some zener diodes maybe?

I used 510 ohm because "This Way Worked" 🤣, joke joke...i went a little higher and my lights began to dim so 510ohm was the sweet spot for my setup. 

Genuinely though please take the time to post a better wiring diagram if you can think of a way to get Anti-Flicker circuitry in our coaches in a simple DIY way we can all follow because it would help us all out, even better yet a video would be fantastic to follow.

[Rallymatt]

Thanks for the video Richard and sharing how to do it. A pretty easy to follow and achieve for most modellers with basic equipment project. You used warm white LED strip, I used warm white on my battery powered ‘Magic Lights’ install on the MK1s, I made those yellowy on purpose to look like the old incandescent lighting, with a 1k resistor; I notice the MK3s your way have that modern blue white look, is that from the coach windows or did you get it another way? 

[Richard-358946]

Thanks Matt, i do hope the video helps people out, at the very least ive shown how to get inside the coaches 😁, the Mk3's look blue tinged in the video but i think that is just the light bouncing off the blue interior and playing tricks on the camera, in person they are warm white light emitted through the windows. Simply just warm white led stripes cut down and put in the roof area 👍 no hidden trickery👍

[Too Tall]

No doubt your videos are always helpful and enlightening Richard 👍 

[Too Tall]

Editing time seems very short , so added as separate post !

 My soldering skills are very basic, so the less I have to do the better, hence why I would opt for a ready made rectifier. I did not intend my post to be a criticism, so apologies if it came across that way. 😊 

[RB51]

@Too Tall - the editing time is set at 15 minutes. If you are finding that to be any different please let us know. R-

[96RAF]

I initially used stripped out IKEA led lighting for my coaches cut down as required. They were also grouped in 3s which seems to be fairly standard. Nowadays I simply cut to length from a long roll of aftermarket kitchen cabinet adornment stick on led strip, again grouped in 3s.

[Bulleidboy]

I used 12v LED's from a five metre roll bought on ebay. I put a resistor in the circuit, no bridge rectifier, and used, in this case, wheel contacts from DCC Concepts. A dab of Tamiya clear yellow lacquer on the LED's gave the period lighting. The carriages shown have been operating for about five years with no problems.

 

I

Edited March 7 by Bulleidboy
amendment

[gilbo2]

To really simplify things, did you try the led's without the capacitor or diodes, they would then work under half bridge rectification but you my notice flicker and see sensitivity to pick up issues. Might be acceptable though for the application?

Edited March 7 by gilbo2

[gilbo2]

@Bulleidboy, great minds think alike, that's what I'd have done 

Edited March 7 by gilbo2

[Grenkin]

Is it good practice to add a way to switch on/off the lights?

I've seen in @Rallymattvideo used magnet switch, this is best approach or is there something better?

[gilbo2]

4 minutes ago, Grenkin said:

Is it good practice to add a way to switch on/off the lights?

I've seen in @Rallymattvideo used magnet switch, this is best approach or is there something better?

For me its down to personal preference rather than good practice. If you want to see coaches with lights off in sidings for example, then yes, a switch would come in. If they were battery powered rather than track, then definitely a switch .

Otherwise, I'd keep things simple, less to go wrong.

[ateshci]

There are bridge rectifiers to free one from the hassle shown in the tutorial. To do away with the capacitor isn't one of the brightest (sic!) ideas. Keep in mind that the best effect is still achieved when you use two 0,3F supercaps in series ( to make them operate @5V ), a dropping resistor, a 5V1 zener, and a cheap self-adhesive LED strip that can be cut to size.

To switch on/off a bit more of electronic tinkering is necessary if you don't want to use a microswitch to operate from underneath. The are latching Hall-ICs around that work by magnetism, have neglectable current draw, and keep their state down to 2.5V.

 

[ateshci]

The 15mins had expired, so:
 >>There are latching Hall-ICs around that work by magnetism, have neglectable current draw, and keep their state down to 2.8V.<<

 

Edited March 7 by ateshci

[Rallymatt]

Latching reed switch is an easy component to add to the track powered lighting solution Richard has done, it’s down to personal preference if you want that option. Obviously on a battery set up it’s a must to have some form of switch, although I have been known to leave lights on overnight a few times and batteries still going strong 🤣