Lighting Trains

[chadbag]

2 hours ago, gavino200 said:

 

I tried: 

removing the LED --> nothing lights

replacing the removed LED with a conductor ---> then only the final LEDs light. The LEDs before the cut point don't work.

I attempted to replace the LED with an SMD resistor. This should work, but it's very tricky and I haven't succeeded.

 

 

 

Can you replace the LED with a diode?

 

You can buy individual LEDs and make your own strips.

 

[chadbag]

@gavino200

 

Here are your KATO compatible brass strips

 

https://store.sbs4dcc.com/SBS4DCCNScaleKatoPickupContactConnectorStrip.aspx

 

 

[gavino200]

1 minute ago, chadbag said:

 

 

Can you replace the LED with a diode?

 

I'm not sure what a diode would add that a resistor wouldn't. Do you mean just to complete the circuit? I did that with a wire. I think if there's not enough resistance it upsets the balance and the "extra" circuit gets too much current. 

 

I'll experiment a bit more with this later.

 

1 minute ago, chadbag said:

 

You can buy individual LEDs and make your own strips.

 

 

Yeah, I could. But I want to spend my time doing stuff that's more rewarding. 

 

 

I actually have some that would work. I bought them for my platform lighting but decided I didn't like them. But I'm looking for something robust and simple. I'd like to be able to knock these out with a minimum of time and effort.

[chadbag]

37 minutes ago, gavino200 said:

 

I'm not sure what a diode would add that a resistor wouldn't. Do you mean just to complete the circuit? I did that with a wire. I think if there's not enough resistance it upsets the balance and the "extra" circuit gets too much current. 

 

 

I was just thinking  that since the LED is a diode, replacing it with another diode is as close to the original circuit as possible.   I am not an electronics expert by any stretch of  imagination

[gavino200]

43 minutes ago, chadbag said:

 

I was just thinking  that since the LED is a diode, replacing it with another diode is as close to the original circuit as possible.   I am not an electronics expert by any stretch of  imagination

 

I tried it. With a diode and with a 100 Ohm smd resistor. No joy. It wouldn't be a great solution anyway as I'd still have to fold the end of the strip under. That could be bulky. At very best it's an inconvenience. Small when done a few times. Annoying when repeated a thousand times. I'm looking for a long term solution to train lighting.

 

 

[cteno4]

The led strips generally 3 leds in series with a dropping resistor to match them to 12v. Cutting in between the set will mean you need to trace the leads and wire in an additional resistor in series with the remaining led(s) and resistor to compensate for current drop lost led(s) in the set. If you don’t drop the current with an additional resistor on a set of 2 or 1 you cut down to it will just fry with 12v pretty fast.

 

there are some led strips that can be cut at every led as it’s basic a 12v bus with single led/resistor sets for each module.

 

btw, the bridge rectifier will take a volt or so off your input voltage, throw the voltmeter on it to see what it’s putting out to make sure it’s <=12v dc.

 

Cheers,

 

jeff

[gavino200]

15 minutes ago, cteno4 said:

The led strips generally 3 leds in series with a dropping resistor to match them to 12v. Cutting in between the set will mean you need to trace the leads and wire in an additional resistor in series with the remaining led(s) and resistor to compensate for current drop lost led(s) in the set. If you don’t drop the current with an additional resistor on a set of 2 or 1 you cut down to it will just fry with 12v pretty fast.

 

I think this puzzle is beyond my ability to solve.

 

15 minutes ago, cteno4 said:

 

there are some led strips that can be cut at every led as it’s basic a 12v bus with single led/resistor sets for each module.

 

Thanks. I'll be seeking these out when the current stock runs out. 

 

15 minutes ago, cteno4 said:

 

btw, the bridge rectifier will take a volt or so off your input voltage, throw the voltmeter on it to see what it’s putting out to make sure it’s <=12v dc.

 

 

 

I don't think it matters much. The voltage is in excess. I still have to drop it down with a 2.2K Ohm resistor. 

[cteno4]

Each of the 3 led modules is just a series of

 

— resistor — led — led — led —

 

each led drops about 3.3v and the resistor about 2v for 12v power supply. If you want the leds to run at 20ma then the resistor value int the module would be

 

R = V / I or R = 2 / 0.02 = 100 ohm

 

if you clip in the module down to 2 leds you would get

 

— resistor — led — led —

 

And since it’s the same resistor you are asking it to drop 5.4v (12 - 3.3 - 3.3) 

 

so the current it will let thru to the leds will be 

 

I = V / R or I = 5.4 / 100 = 54ma is a poof on the 20ma leds!

 

to fix this you would need to add back a resistor to make up for the led voltage drop of the lost led in the series

 

— resistor — led — led — new resistor —

 

new resistor would need to do a 3.3v drop to match the drop of the missing led so

 

R = V / I or R = 3.3 / 0.02 = 165 ohm

 

make sense?

 

wasnt sure what voltage you are running your dcc at but 2.2k resistor will drop the current plenty even if running at 14v.

 

jeff

[gavino200]

I've done five of these now. I'm very happy with the look and function. But it's really quite a difficult technique. I'm evolving a decent method as I go, and I have a couple more adjustments I can make to streamline the process. But soldering SMD components onto free wire is just inherently a tedious thing to do. 

 

The main limitation is still the size of the capacitor. It needs to be carefully guided into an unobtrusive place so that it doesn't impede closing the shell or remain visible through the window. To make this possible, the components need to be soldered onto wire with some slack to allow adjustment. 

 

A 100uF capacitor thin enough to fit between the roof and the interior dividers might change this completely. It should then be possible to prebuild the whole assembly, then simply, apply it to the shell, and simply solder one pair of wires to the pickup strips. I hope this is possible because I love the capacitors and my compulsive obsession with flicker will make me go through even an install this tedious.

Edited February 24, 2019 by gavino200

[gavino200]

1 hour ago, cteno4 said:

 

 

make sense?

 

 

 

 

Yes. But a downside is that the circuit path needs to be left intact in order to do this, so you can't simply shorten the strip to fit the carriage length. After fitting resistors I'd still have a strip that is too long, that I'd have to fold over in order to fit in the coach. The goal isn't just to reduce the light, but do decrease the length of the strip. If single snip friendly strips are available that wold be a much better way to go. 

Edited February 24, 2019 by gavino200

[cteno4]

Yeah the circuit paths usually are not in a layout to modify like this easily. Best just keep it to 6 leds!

 

jeff

[gavino200]

So I finished the Orient Express. Below are the steps involved. It works very well. But I'd only recommend for someone who, like me, has an obsession with light flicker. It's very time consuming and fairly tricky. I had to use magnification. After a learning curve of 6 cars and a night of sleep to consolidate, this car took me 50 minutes. At that rate a whole train takes approximately a full day. I would do that if I really have to, but I'd rather not. I'm going to hold off on doing any more of these until I can find some smaller capacitors to experiment with.

 

Here's the method anyway. Please feel free to suggest errors or improvements.

 

Step 1

 

The rectifier is soldered to the pickup strips using striped 30g wire. Then the pickup strips are inserted and the position of the rectifer is adjusted. 

 

 

Step 2

 

A small segment of insulation from two pieces of 30g wire are striped of insluation. The wires are then soldered to the capacitor. This leaves intact 30g wire as imput and output for the capacitor. Next cut one wire short and solder a 2.2K Ohm SMD resistor to the wire. Solder another piece of 30g wire to the other side of the resistor. You're left with this (below)

 

 

Step 3 

 

Place the LED strip in the carriage shell and estimate where you want to put the various parts to hide them best. Then cut the wires accordingly. In this case I put the cap sitting on the floor. This was the only car I did like that. This car has no seats/walls and the windows are partially obscured with "bars". Also the window run the entire length of the car so there's no place to hide the componants a the end. Fortunately the cap is quite well obscured sitting on the floor here. It's below window level.

 

Next solder the wires from the capacitor assembly to the rectifier. Careful with polarities. 

 

 

Step 4

 

Use tacky glue to fix a strip of paper over the LED strip. This is necessary for ideal light diffusion. I use a tiny string of tacky glue on each side of the strip. If you smear the whole thing, it causes a short and you need to wait forever for the glue to completely dry. Notebook paper is thinner than printer paper and doesn't decrease the brightness, which is perfectly calibrated with the 2.2k Ohm resistor (thanks Dani). If possible, using an old notebook with slightly oxidized pages enhances the warm white nicely.

 

 

Step 5

 

Solder the wires to the strip. Careful with polarity. The strip is now upside down. Remove the sticker backing from the LED strip. Place the strip on the shell roof and use a tweezers to steward  the components and wires carefully into place as you close the shell onto the chassis.

 

Finished car

 

[gavino200]

Question about capacitor position. Does it matter where the capacitor is placed relative to the LEDs? Do I need to place the  caps between the rectifier/resistor and the LEDs? Or can I place the caps anywhere along the LED strip.

 

The strip of 6 LEDs has three pairs of solder pads. One in the middle and one at each end. Would the capacitors function if I placed one at the middle pads and one at the opposite end to the rectifier.

 

If so that would make the unit much smaller and more robust.

 

 

[Kiha66]

Since the the sets of leds are wired in parallel, you can add it to any of the solder pads and get the same effect.  Just make sure to keep the polarity correct! 

[gavino200]

On 2/8/2019 at 6:22 PM, chadbag said:

 

I've asked the Streamlined Backshop sales if they have dimensions for the various axel wipes they have so I can see what will work best in the various wagons.

 

 

 

Were you ever able to work out which wipers were Fleischmann compatibe?

[chadbag]

23 minutes ago, gavino200 said:

 

 

Were you ever able to work out which wipers were Fleischmann compatibe?

 

There won't be one that is "Fleischman" compatible since the various Fleischmann bogies are not all the same.  But they did not get back to me and I have not yet investigated further.  I will be at some point though.  When I am ready to DIY lights on my IC cars and other Euro wagons.

[cteno4]

I think you may want to wire them between the rectifier and the dimmer resistor so that you keep the current limited. If I remeber my electronics clearly enough if in this situation the current supplied by the cap discharge would not be limited by the first resistor. when wheel power is lost the strips would be going at the full current of the strips, not the lower current you have them at by adding the external resistor. This is because the circuit becomes

 

— led strip ————— dimmer resistor — bridge rectifier — track (no circuit when there is a pickup disruption)

|                        |                                                    X

|                     Cap                                                X

|                        |                                                    X

—————————————————————— bridge rectifier — track  (no circuit when there is a pickup disruption)

 

so it would get brighter when you have track pickup disruptions. You may not notice this up flicker, but it will draw more current and thus deplete the cap faster (I think).

 

i think you want

 

— led strip — dimmer resistor ——— bridge rectifier — track (no circuit when there is a pickup disruption)

|                                                        |                 X

|                                                    Cap              X

|                                                        |                 X

———————————————————— bridge rectifier — track  (no circuit when there is a pickup disruption)

 

cheers

 

jeff

[chadbag]

 

I think we should have a sticky tgopic on train light color and various trains.  A table like the KATO DCC topic where we can list the train and what color lights we installed and why (ie, what prototypical evidence did you find).  It would save each person from having to research the same trains others have already researched.

 

[gavino200]

9 minutes ago, cteno4 said:

I think you may want to wire them between the rectifier and the dimmer resistor so that you keep the current limited.\

 

 

Thanks Jeff. I'll make this change.

[gavino200]

6 minutes ago, chadbag said:

 

I think we should have a sticky tgopic on train light color and various trains.  A table like the KATO DCC topic where we can list the train and what color lights we installed and why (ie, what prototypical evidence did you find).  It would save each person from having to research the same trains others have already researched.

 

 

You mean like bright white vs. warm white? I just use warm for old and bright for new.  I'd draw the line somewhere in the 80s. I'm not sure this is worth a sticky. 

[chadbag]

Just now, gavino200 said:

 

You mean like bright white vs. warm white? I just use warm for old and bright for new.  I'd draw the line somewhere in the 80s. I'm not sure this is worth a sticky. 

 

I don't think it is that simple

 

[gavino200]

Just now, chadbag said:

 

I don't think it is that simple

 

 

It's definitely worth a designated tread if you wan't to make one. 

[chadbag]

11 minutes ago, gavino200 said:

 

It's definitely worth a designated tread if you wan't to make one. 

 

I would if I had any Google-fu but as I generally avoid Google (for the actual spreadsheet database) I don't have that.

 

[cteno4]

It might be good to have a google account for the forum to host this sort of thing so it stays with the forum and we have dedicated folks for each spreadsheet to maintain it. Problem if it’s a shared thing on a members private account and they drift off the forum with time. Let me talk to Martijn about setting this up using our main admin email address so the google account will stick with the forum not any individual member.

 

jeff

[cteno4]

Hmm I’m not sure if the cap inside the dimmer rectifier might be charged at the dropped voltage so would put out at the same now that I think about this more. It might also mean you could use 16v caps. Caps are strange beasts at times in the logic.

 

My main electronics education was age 5-20, that’s a long time ago for me and the cobwebs get in the way at times.

 

but putting the cap between the rectifier the dimmer resistor I know it should perform correctly, just not sure the alternative will work exactly the same.

 

jeff