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chadbag

JNSF DIY lighting project (PCB based)

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gavino200
1 hour ago, chadbag said:

 

Based on specs, I am partial to the LT1118CST-5 voltage regulator as it is small and a lot cheaper than the toshiba (that I have found so far).

 

Is it size compatible with a 3.3V regulator?

 

Having to solder on a lot fewer caps would be a huge advantage.

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chadbag
14 minutes ago, gavino200 said:

 

Is it size compatible with a 3.3V regulator?

 

Having to solder on a lot fewer caps would be a huge advantage.

 

I have not looked at 3.3V output voltage regulators.  Find some and we can check their form factor (package).  These chips are all packaged in "standard" sizes (about 100 million standard sizes).  I've been trying to figure out this layout software -- it comes with "footprints" for the various package sizes, which I have been looking up on the data sheets.

 

Can you find some 3.3V regulators for me to look at?

 

 

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gavino200
1 hour ago, chadbag said:

 

Can you find some 3.3V regulators for me to look at?

 

 

 

Here's one. I think Jeff also said he might have some lying around that he'd look for.

 

https://www.adafruit.com/product/2165

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cteno4
11 hours ago, chadbag said:

 

One issue is that the warm white and bright white are usually listed as 3-3.3v

 

 

What’s the concern? The dimmer resistor is doing the voltage drop and current limiting in the 5v circuit. I think the 3.3v regulator will drive them as I’ve driven White leds with 3v batteries.

 

jeff

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chadbag
1 minute ago, cteno4 said:

 

What’s the concern? The dimmer resistor is doing the voltage drop and current limiting in the 5v circuit. I think the 3.3v regulator will drive them as I’ve driven White leds with 3v batteries.

 

 

There is no concern in a 5V system.  The concern is if the 3.3V system, with all the various tolerances, will drive a string of LEDs whose forward voltage is about the same, once you put the other stuff like minimal resistors etc. into the system.    It might.   My electronics knowledge ended in a CS class I had in the 80s.... 🙂   We can try it and see.

 

The other color LEDs that have a 2,x forward voltage would not have raised a concern flag.

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cteno4

As long as the voltage is enough to light the leds then the resistor will just be doing increasing current limiting and thus dimming the leds. Resistor is the only component on the output side of the regulator along with the leds.

 

I produced a bunch of little circuits for some dollhouse friends with 3v coin battery and small pot to drive white leds. Works great. Don’t even need to put a limiting resistor in the ciricuit for when pot is turned to 0 resistance eas the battery has enough internal resistance to limit the current with the battery voltage right at the led forward voltage.

 

jeff

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gavino200
Posted (edited)

I have something to report from my shinkansen lighting test. I've done the whole train except for the cabs, so I can run the train and see it from all angles. There's a problem that I think we should try to avoid. It concerns using 1206 LEDs at the spacing on the store bought LED strips. I no longer think this is a good idea.

 

I had noticed with my Orient express alternating bright and dull areas. That was essentially fixed by using paper diffusers. However, the Orient express also has beautiful, very detailed and irregular interiors that also break up the light. The shinkansen doesn't have this kind of interior and the difference is very noticeable.  

 

At a "certain" angle - basically standing about two feet in front of the layout. You see the reflections of the lights off the floor of the cars. It's not subtle. It's like searchlights shining out of every fifth window. I took a picture. But the camera doesn't capture the effect well. Imagine the bright spots being brighter and the "less bright" areas looking almost dark.

Looking directly through the windows at "ground level" you don't see this. 

 

There's a second problem which may have a slightly differecnt cause. At the same points - directly under the LED you can see light refracted or reflected (can't tell which) through the plastic "glass" pieces themselves. The clear plastic at the lower part of the window reflects bright light. It really doesn't look good. This may just be from concentrated light at these points. But I wonder if it's caused by the fact that the LED strips are pasted to the roof of the car - higher than in proprietary and aftermarket light sets. Maybe because they are higher they can shine down into the clear plastic at the top surface at a high enough angle as to be not reflected on the first surface. go through the clear plastic,  and get reflected out the window at the lower edge. 

 

Basically, I'd down grade this technique further, at least with these LED strips. I think closer smaller LEDs would be better or maybe essential. I'm turning sour on 1206 LEDs.

 

Again this picture doesn't really show how the problem appears to the eye. To the eye it looks bad.

 

p4JZxlm.jpg

 

 

This is a TORM by the way.

 

6dnH4KZ.jpg?1

 

Edited by gavino200

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Kiha66

I've noticed reflection from the molded floors as an issue in my lighting installs as well, either tinting the light or reflecting oddly and looking unnatural.  To combat this I've been painting the interiors of my cars as I add lights.  Even just putting a dull floor color and leaving the seats makes a huge difference. 

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gavino200
1 hour ago, Kiha66 said:

I've noticed reflection from the molded floors as an issue in my lighting installs as well, either tinting the light or reflecting oddly and looking unnatural.  To combat this I've been painting the interiors of my cars as I add lights.  Even just putting a dull floor color and leaving the seats makes a huge difference. 

 

I'd imagine I'd get away with just applying the clear coat with a brush. I'd rather not completely dismantle all the cars again. I can't imagine there's any real advantage to using an airbrush in this case.

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Kiha66

I just pop the shell off and brush paint the floor (and wall and chairs if I'm feeling fancy).  I think an airbush would be faster but would require a lot more disassembly.  A flat clear coat would probably have the same effect, but I haven't tried that yet.

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gavino200
1 minute ago, Kiha66 said:

I just pop the shell off and brush paint the floor (and wall and chairs if I'm feeling fancy).  I think an airbush would be faster but would require a lot more disassembly.  A flat clear coat would probably have the same effect, but I haven't tried that yet.

 

Nice. Do you paint the seats a different color than the floor/walls?

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Yavianice
4 hours ago, gavino200 said:

This is a TORM by the way.

 

So the picture you took of the Hello Kitty train is equipped with the TORM Kato lighting? I do not own KATO TORM lighting, only WIDE lighting, and I actually kind of like the irregular lights. IMO KATO TORM lights are a bit of a waste since KATO standard lights are so much better, and JR500 lights are so much cheaper...

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Kiha66

Since the interior molding is usually already the seat color most of the time I leave them and just paint the head/arm rests colors.  I usually use tamiya grey for the floor, buff for the walls and white for the head/arm rests.  Tamiya sky is also great for doing the generic cab green color and for the mechanical spaces.  

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gavino200
Just now, Yavianice said:

 

So the picture you took of the Hello Kitty train is equipped with the TORM Kato lighting? I do not own KATO TORM lighting, only WIDE lighting, and I actually kind of like the irregular lights. IMO KATO TORM lights are a bit of a waste since KATO standard lights are so much better, and JR500 lights are so much cheaper...

 

No. I did the Hello Kitty train using a "home made" lighting technique described by Dani. It uses a rectifier, a resistor, and a piece of LED strip lighting.

 

http://www.clubncaldes.com/2017/03/tomix-shinkansen-500-eva-digitalization.html

 

TORM is a brand name. They're ready made interior lights and come in either Kato or Tomix configuration. Reportedly they work well on DC but with DCC they're much too bright.

 

https://www.modeltrainplus.net/collections/torm

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gavino200
5 minutes ago, Kiha66 said:

Since the interior molding is usually already the seat color most of the time I leave them and just paint the head/arm rests colors.  I usually use tamiya grey for the floor, buff for the walls and white for the head/arm rests.  Tamiya sky is also great for doing the generic cab green color and for the mechanical spaces.  

 

Wow! That sounds awesome. Do you have a picture? Are you going to start adding passengers?

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Yavianice
13 minutes ago, gavino200 said:

TORM is a brand name. They're ready made interior lights and come in either Kato or Tomix configuration. Reportedly they work well on DC but with DCC they're much too bright.

I know it is. I own approx 60 of those.

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Kiha66
Posted (edited)

Passengers are definitely on my list, I just need to get a bulk order from china.  The second car doesn't have the headrests and arm rests done yet but you can see just a little color really makes a difference when seen through the windows.  You cant see the specifics so don't worry too much about getting the paint perfect, but the variation makes the cars really stand out.

 

20190303_153444.thumb.jpg.90ec3ff5f9b9fdb682e8075fbf9160ad.jpg

20170930_115725.jpg.17f534c57fc87a1f0d45219d2351041d.thumb.jpg.b6a6c455d7ee13800d2040a1b7dd03ae.jpg

23472949_1817778518251288_4134561236316162139_n.thumb.jpg.e4391b41b2490ac7632f738497b709ce.jpg

 

Edited by Kiha66
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gavino200
Posted (edited)
6 minutes ago, Yavianice said:

I know it is. I own approx 60 of those.

 

Sorry, I misunderstood. 

 

I bought Kato TORMs because I used never be able to get the Kato lights to work right. I've since worked out how to do it, and I agree they look better. 

 

The  purpose of this project is to use capacitors to try to eliminate flicker.

Edited by gavino200

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gavino200
4 minutes ago, Kiha66 said:

Passengers are definitely on my list, I just need to get a bulk order from china.  The second car doesn't have the headrests and arm rests done yet but you can see just a little color really makes a difference when seen through the windows.

 

 

 

 

That looks great. I have just officially been inspired!

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gavino200
Posted (edited)

This is an interesting video. It contains a great description of a home made cap buffered lighting system, a discussion of light diuffusion, and also a discussion of interior customization. Well worth a watch.

 

For his lighting circuit, this guy uses a constant current chip rather than a voltage regulator. 

 

 

Edited by gavino200

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cteno4

This is the constant current circuit I’ve been referring to and we’ve discussed a lot here in a number of lighting threads. It’s really a nice approach as it’s setting the current constant. Not dealing with voltage and current. Very elegant for dc. Only problem is the cap has to go on the power side of the constant current chip so it needs to handle up to 12v and you are back to 25v tantilums or electrolytics. Also the constant current chips are more expensive and not as prevalent as the voltage regulator chips. 

 

Bouncing the light to get diffusion also helps a lot to get a more realistic even lighting in the car from very dimmed leds

 

Its an excellent presentation to boot.

 

jeff

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Kiha66

Kato uses a constant current diode, iirc.  It seems a very elegant and simple solution in a small space.  Like Jeff said the keep alive will have to go before the device for it to work during periods of power loss.

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cteno4

Well it’s not any smaller than a voltage regulator really. Still needs a resistor (to set the current) and the rectifier. The big downside is needing the higher value cap. Their keep alive time seems more than needed for basic antiflicker. Seems like maybe a single 100uf tantalum might work.

 

Using 5v or 3.3v voltage regulators allows the use of ceramic caps that are cheap and small. Electrolytics and tantaliums can start to take up room. I was pretty set to go this direction but i now want to see how the voltage regulator circuit compares.

 

jeff

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chadbag
1 hour ago, cteno4 said:

Well it’s not any smaller than a voltage regulator really. Still needs a resistor (to set the current) and the rectifier. The big downside is needing the higher value cap. Their keep alive time seems more than needed for basic antiflicker. Seems like maybe a single 100uf tantalum might work.

 

Using 5v or 3.3v voltage regulators allows the use of ceramic caps that are cheap and small. Electrolytics and tantaliums can start to take up room. I was pretty set to go this direction but i now want to see how the voltage regulator circuit compares.

 

jeff

 

I will post some pictures but I got some really small 0.15A 5V voltage regulators today in the mail.  Not like the gigantic (relatively speaking) ones I've also gotten.  0.15A should be more than enough as we are not driving the LEDs to their full 20ma capacity and we use 5-10 of them most likely.   I'll post some comparative sizes pics and also some comparitive sizes on the various rectifiers I have gotten tomorrow when I have a chance to inventory and get examples out.

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