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chadbag

JNSF DIY lighting project (PCB based)

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cteno4

i would think as thin as possible as its not going to get much flexing and will be attached to the roof probably. i guess if not attached to the roof and just supported from the ends it could sag with time, not sure how resistant the fiberglass is when really thin to sagging with time. the components in the middle are pretty light ones, its the caps that are the most dense along with the rectifier and voltage regulator. at the one end.

 

jeff

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chadbag

OK, so maybe 0.6mm.  They allow 0.4mm but the EM13 boards are pretty thin as is (and stiff).

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chadbag
44 minutes ago, chadbag said:

OK, so maybe 0.6mm.  They allow 0.4mm but the EM13 boards are pretty thin as is (and stiff).

 

so, I will do 0.8mm as the engineering fee goes up a lot for 0.6mm for this board (at least the version I posted a couple nights ago).  We'll see once I upload the final board.

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gavino200
6 hours ago, chadbag said:

One question for the team:   What thickness of board should we use?   The Ersatz-EM13 decoder is 0.6mm.  It is not bad but I thought maybe 0.8mm?  (Traditional boards in electronics seem to be about 1.6mm or so based on what I see to buy online for test boards).

 

 

 

They don't really need to have any strength. And thinner is easier to break to shorten. I'd vote for thinner.

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gavino200

TORMs are 0.8mm and they're super easy to break with a minimum of scoring.

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gavino200
21 hours ago, chadbag said:

 

I'll probably get 100 made as a sample run (since the price between 10 and 100 is like $20 delivered or something -- 10 pieces is like $2.60 each and 100 samples are like 40 - 50 cents each, delivered).  So those who want to get some to play with can just cover whatever the cost is for me to get them plus postage to your place.  Once we like them we can do bigger runs (they will get used up fast since most trains are like 4 - 6 - 8 -10 or so cars or more and we all have arge fleets 🙂 and 1000 is like 25-30 cents each IIRC  ).

 

 

 

Count me in. Just PM me with a number and I'll paypal it to you.

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cteno4

I’m in as well.

 

Jeff

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Sheffie

I feel like I would like to support this work, but I'm nowhere near ready to assemble my own components on a circuit board.

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chadbag
10 hours ago, Sheffie said:

I feel like I would like to support this work, but I'm nowhere near ready to assemble my own components on a circuit board.

 

IN what way "not ready"?  Not to that part of your layout needs?  Not handy with a solder iron?

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Sheffie
16 minutes ago, chadbag said:

 

IN what way "not ready"?  Not to that part of your layout needs?  Not handy with a solder iron?

I have a soldering iron but no real experience with it. And no components to solder onto the board 

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Martijn Meerts

A version that allows daisy chaining could be interesting, so that if you have have custom couplers, you could theoretically control the lights of all boards with a single function decoder. It'd get really expensive to digitally control the lights in a 16 car train if each car needs a decoder, even with the cheapest function only decoders.

 

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chadbag
32 minutes ago, Martijn Meerts said:

A version that allows daisy chaining could be interesting, so that if you have have custom couplers, you could theoretically control the lights of all boards with a single function decoder. It'd get really expensive to digitally control the lights in a 16 car train if each car needs a decoder, even with the cheapest function only decoders.

 

 

You could actually do that here I would think.  Just run a bus wire to all cars through your coupler and come off it into the decoder inputs on the boards on each board.   You just need a function decoder that can handle the current of 16 cars worth of LEDs.  A real EE type would need to look at and confirm my statements.

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Martijn Meerts

Optimally, you'd use the board itself as bus, just have 2 traces go from 1 end to the other, so you don't have to run extra wires. Of course, for Japanese models it's not much of an issue, since pretty much all cars have power pickup strips running the length of the car, but European brand cars don't have any pickup at all, and the power pickup system in them is pretty terrible anyway.

 

I've been looking at things like current conducting 3D printed couplers, or custom power pickup inspired by how the Japanese brands do it, but I haven't had the time for any of that really. Another option would be to try and manufacture very simple decoders that control lighting and not much (if anything) else. The components on them are dirt cheap, and they could be integrated in a lighting board, so you don't have to go for the smalles components either. But you do need someone who knows how to write the software to respond to DCC commands and program CVs and the like. There is OpenDCC, so it's quite possible to find code that can do all that, but it'd require a lot of time.

 

 

 

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chadbag

The Japanese style wouldn't help you with controlling it from a single decoder.   It does make it easy to run a board though since the power pickups are there already.

 

 

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Martijn Meerts

Ah yeah, of course, wasn't really thinking it through. Although, I guess you could add traces on the board to solder a miniature connector to them, and the use those connectors to hook up the cars. Not pretty, and doesn't really work for all cars, but it's an option.

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Kiha66

While LEDs in parallel off a single resistor are not the ideal arrangement (they will start burning out at some point as one will have a slightly lower internal resistance and draw more current), this should work fine assuming you use all the same type of LEDs.

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cteno4

Chad, 

 

have you breadboarded this all to verify it all works as laid out? Mainly concerned about the voltage reg caps are all happy as is. Know you got them off the spec sheets but always good to verify. Breadboard pcb is great to solder up a Frankenstein to test on something like this with small bits of wrapping wire soldered in and resistor leads for busses.

 

if I get a little time over the weekend I can try to do one, but I’m not sure I have things close to the buffer caps or not. Sadly parts are strewn across many boxes trying to get things more organized and these are the tiniest of bits! I think I had a small smd ceramic cap series set, but have to see if I can find them and there are ones close.

 

jeff 

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cteno4

Actually in this case it won’t burn out as it’s only a couple of ma in total to the leds, but if one does start to draw more the it will light brighter (but still way below limit) and the rest not light. I seem to remeber reading a while back that it was at higher current that the differences in draw would show up more — and of course potentially fry the one higher current led as total ma are over the led of a single led and then perhaps all of them down the line. I think it was at the low end as it was against the desired pump as many ma as possible in this discussion.

 

the other thing I remeber is that I think the forward voltage goes down with lower current, so the 3.3v voltage regulator should work and thus let you use lower voltage caps.

 

one thing beware of cheap ceramic caps that say like 10-25v and 100uf or even lower ufs on ebay and aliexpress. I’ve noticed that A they can be too inexpensive to be true and B some in the description then say nf not uf that may be in the title or the selection values at the top. Smd Ceramics seem to just be creeping up into the higher capacities and voltages to replace tantaliums. Also I’ve noticed some of the cheap ceramic smd caps have come with no labeling at all, not good...

 

jeff

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cteno4
47 minutes ago, Martijn Meerts said:

 

I've been looking at things like current conducting 3D printed couplers, or custom power pickup inspired by how the Japanese brands do it, but I haven't had the time for any of that really. Another option would be to try and manufacture very simple decoders that control lighting and not much (if anything) else. The components on them are dirt cheap, and they could be integrated in a lighting board, so you don't have to go for the smalles components either. But you do need someone who knows how to write the software to respond to DCC commands and program CVs and the like. There is OpenDCC, so it's quite possible to find code that can do all that, but it'd require a lot of time

 

I think that was part of the dcc stuff don was working on with trainaidsa. They wanted a simple lighting/end car decoder and starter power pack. I think do was surprised how cheap the circuit was, like you said mainly programming.

 

jeff

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Martijn Meerts
46 minutes ago, cteno4 said:

 

I think that was part of the dcc stuff don was working on with trainaidsa. They wanted a simple lighting/end car decoder and starter power pack. I think do was surprised how cheap the circuit was, like you said mainly programming.

 

jeff

 

Yeah, I actually have one of their developer starter kits, but never got around to trying it. It didn't include any loco decoders or anything.

 

1 thing that makes loco decoders expensive is that their size. For N-scale they need to be really small, so you can't really solder them yourself. If you can basically integrate them with a lightboard you have a lot of space to work with. I'm pretty sure I'd be able to solder the components and get the code to work, but I'm no good at designing the actual hardware.

 

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chadbag
2 hours ago, cteno4 said:

 

have you breadboarded this all to verify it all works as laid out? Mainly concerned about the voltage reg caps are all happy as is. Know you got them off the spec sheets but always good to verify. Breadboard pcb is great to solder up a Frankenstein to test on something like this with small bits of wrapping wire soldered in and resistor leads for busses.

 

 

Not yet.   I don't have any actual breadboard pr anything but do have a spool of "buss 30" wire and was planning on soldering together the circuit using example values to test this weekend.

 

The usable parts/values in this circuit are legion, meaning many different combinations.  So there is no one circuit to test and verify.  I am more interested in testing the circuit path.

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gavino200
9 hours ago, Martijn Meerts said:

 but European brand cars don't have any pickup at all, and the power pickup system in them is pretty terrible anyway.

 

 

Have you ever tried one of the "wheel wiper" pickup lighting kits? If so are they problematic? Perhaps the capacitors could help. I'm interested in lighting my European coaches.

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cteno4
4 hours ago, Martijn Meerts said:

Yeah, I actually have one of their developer starter kits, but never got around to trying it. It didn't include any loco decoders or anything.

 

1 thing that makes loco decoders expensive is that their size. For N-scale they need to be really small, so you can't really solder them yourself. If you can basically integrate them with a lightboard you have a lot of space to work with. I'm pretty sure I'd be able to solder the components and get the code to work, but I'm no good at designing the actual hardware.

 

Yeah I think just the prelim work was done on the decoder side. Ardesh was keen on finding niches like a budget throttle and the odd accessory decoders as he knew the end car decoders jacked up the dcc price for most Japanese trains. Lighting decoders didn’t need to be quite as micro as loco to fit into tiny spaces.

 

Ardesh was an excellent businessman (and a very good egg), finding the niches that had little or no competition and was a big relief/fix for the customer to fill that need. I’ve still not gotten as good a screw replacement in price and quality to beat his. I should have asked his sons to buy a big box of them! Since I had lunch him every month or two I would just buy stuff as needed and he brought it to lunch. this is how we started having lunch as I realized he lived like 5 miles from me and shipping was as much as lunch so I offered to buy him lunch to deliver my first package as I was intrigued by a guy would would make 100,000 screws because he knew enough friends were frustrated buying marklin screws from Europe for very high prices. I miss him dearly.

 

jeff

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chadbag

Success

 

I wired up the circuit (using 2 bulb  LEDs and a single 100uF Tantalum cap  [tested up to 3 of the 100 uF] instead of a row of smaller value ceramic caps as it was easier to solder).   The rectifier bridge is a larger model (about same spec -- just physically larger) that I had bought a small number to test with the LED strip lights but functionally it is the same as the MB6F/S ones.   The voltage regulator was a 5V one  L7805CV with 3 legs (not SMD).  The board is set to take this one or 2 different smd regulator packages.  I used a 0.22uF tantulum on the input to the voltage regulator instead of the 0.33uF ceramic as I had some I ordered by accident and it shouldn't really matter I don't think in our simple circuit.  I used a 0.1uF ceramic on the output and a 75 ohm (instead of 100 ohm as I had a bunch) resistor into the 100UF tantulum.  After the 100uF tantalum I used a 1K ohm "dimmer" resistor since we are not at 12V but rather 5 and then I put 2 bulb LEDs I had taken off of KATO lightboards when doing DCC conversions. 

 

I tested by using my DCC test/programming track and the DCC output from the D&H programmer box.   I just held the rectifier pins up to the track (with a pair of fine needlenose on one track to make the distance smaller).   Varying the anti flicker capacitance (trie 1x 100, 2x 100, 3x 100uF) did lead to a longer fade.  Need to do more testing as it was hard to hold on well.  It seemed though that as soon as it moved off the track it started to dim.  The fading time varied with the capacitance.   I need a better test setup.  But I expected to see a partial second of full brightness before it faded off.  I think I will add a few more capacitor pads on the board.  Instead of 6, maybe 8 or 10 if they will fit.   WQe can't cram them in as close as maybe the commercial boards as we have to solder them by hand 🙂

 

 

IMG_0800.thumb.jpg.dd2cfcc6c1febef555b14d099321b17e.jpgIMG_0804.thumb.jpg.486e1d31a294907eb4875d3aab49d2ac.jpgIMG_0801.thumb.jpg.1ae53625e0aa310a2ebea7dcf056bbb1.jpg

Edited by chadbag
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