I was also thinking of the issue of sticking the completed board in the passenger car.  That is four times the footprint of my lighting board, that's a pretty good sized board.

Here you go, 1.5" x .675", even includes the DCS choke.  That's just about half of the 2 sq/in.

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gunrunnerjohn posted:

I was also thinking of the issue of sticking the completed board in the passenger car.  That is four times the footprint of my lighting board, that's a pretty good sized board.

Here you go, 1.5" x .675", even includes the DCS choke.  That's just about half of the 2 sq/in.

I’d like a gerber file and BOM of that...  

GREGM; I think it's commendable that you are brave enough to launch into designing and ordering your own PCB's from OSH Park. Hopefully they will work as you envision. I just received 2 orders of boards from OSH Park using grj's Gerber files which he kindly provided, and they look great. Kudos to grj for all the research and design work!  My first impression of the boards is how small they are. Yikes! I know they are going to be fiddely to build, but hopefully I am up to it. Time will tell I guess. I expect it will be one of those things where just as you finish the last one, you find the best way to do it. 

Rod

Rod, I always find something that could be done better AFTER I send the boards out to fabrication!

Ted, I just picked parts out of the PCB package, I'd have to scout them out.  I know they exist, because all the 3D models are of real parts.  The one I did specifically look up was the 470uf capacitor, I was trying to do it with a 13mm part, but couldn't find one that was the right value.

I have made a couple of additions to the circuit design.  I will wait until after I receive the ordered PCB boards to layout a new PCB to match this schematic.  Once I actually see the board I can work on placing the components closer together.

 

 

Let me know if you see something wrong.

Thanks for every ones input.

 

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John,

I reread your post at the top of this page again.  I see the confusion now, my board isn't 2 inches square, it is just under two square inches of PCB material.  I calculated the dimensions as 1.95 inches by .85 inches.  OSH Park calculated the dimensions as 1.96 inches by .86 inches.  My first attempt was (my calculation) 2.25 inches by .85 inches.  Decreasing the length of the boards reduced the cost for the three boards to under $8.00.

 

Rod,

Got distracted, meant to say Thank You when I typed this post.

Last edited by GregM

I'm confused about the PTC, the regulator has current limiting, the chance that the PTC will be used is pretty small.  You'd be better off with a universal design to toss in the 22uh choke for DCS in that spot.

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I missed that 10mm cap, I could have made that board smaller with that one.  With the 10mm diameter, it's now 1" x 3/4".

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gunrunnerjohn posted:

I'm confused about the PTC, the regulator has current limiting, the chance that the PTC will be used is pretty small.  You'd be better off with a universal design to toss in the 22uh choke for DCS in that spot.

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I missed that 10mm cap, I could have made that board smaller with that one.  With the 10mm diameter, it's now 1" x 3/4".

 

The PTC is there to prevent the wires from melting in the event of a derailment that causes a short between the rollers.  I have read that recommended here.

I figured the PTC out after I spotted the three wires coming in, makes sense now.

Since most of the time the wiring is down under somewhere, I just stick the PTC in there.  Typically, my regulator is on the roof of the car, and I didn't want to run separate wires from each pickup all the way up there.

GREGM; I see you have added the 22 uH choke and a PTC fuse to your schematic. Must be just me but I am not sure I understand why you have 2 separate inputs for the center rail rollers, one thru the PTC and the other bypassing it. What did I miss! 

Rod

Rod, the PTC is there to prevent the issue of one roller landing on the outside rail and cooking the wire between the two pickups.  In normal operation, both sides of the PTC have the same voltage on them, the center track voltage.

gunrunnerjohn posted:

I missed that 10mm cap, I could have made that board smaller with that one.  With the 10mm diameter, it's now 1" x 3/4".

John that is a petty nice compact board layout, and it looks like it would be simple enough to build, even for a hacker like me. Is that a complete ready to go Gerber file? And how did you create it so fast?

Rod

Last edited by Rod Stewart

It's not a Gerber file yet, but that's just because I didn't export it from the PCB layout package.  As for the creation speed, there are only a handful of components on the schematic, I just picked representative package sizes for the parts and then plopped them on the circuit board.

Before I committed it to Gerber, I'd probably want to insure I can actually buy the parts represented.  They are real part sizes, but they may not be readily available.  I refer specifically to the pot and the choke, the rest I know are available in that footprint.  I also thought that maybe trying to get a pot that is adjusted from above would be a better option.

Wow John, that is fantastic, thanks for taking the time out of your schedule to whip that up.  I especially appreciate that this is a leap of faith for you inasmuch as it competes with your kit already being sold by Hennings. But it is a great help for those of us who want to roll our own, and don't have the talent or time to whip up our own board design, and find thru-hole building easier.

It should be possible to make a 100 ma version simply by switching R1 & R2 to 12 and 50 ohm values respectively, correct? I may also poke around and see if Digi-Key has a larger value C1 cap, still in a 10 mm body style and 35V, accepting that it will be taller of course.

As always, my hat is off to you! 

Rod

Thx John, ordered some boards to play with and try out on some cars.  Checked the option for 2 oz copper, 0.8mm thickness.  Same price.  Hope you at least get royalties from OP.  Nice touch with the JWA on the bottom of the board.  

A01CEE74-E037-41F7-B836-622516EBA461

 

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Last edited by TedW
TedW posted:

Nice touch with the JWA on the bottom of the board.  

I wasn't going to let you get away without at least posting a small ad.

So with the latest incarnation, the bare per-board cost is down to ~$1.30...and if you do eBay for components, the total out-of-pocket is $2 per board!  Wow.

So I realize the thread is titled pax cars, but mate this with a 99-cent (free-shipping from Asia) eBay relay module, set the current to max (45 mA) and for $3 you have an insulated-rail relay module for gate-crossing mechanisms, dual-aspect signals, etc..  Again, this means you must know which end of a soldering iron to hold, but I believe this would be the lowest cost ever for an insulated-rail relay module.  

idea-thinker posted:

Below is a link to a circuit that I just purchased which accepts AC in and outputs DC. It has an adjustable output as well. The cost is about $2.00 each The size is about 3/4 in by 2 in and is about 7/8 in tall. This should cover most the of questions being asked in this thread.

https://www.ebay.com/itm/AC-DC...p2060353.m2749.l2649

That's certainly an option, but note that it's twice the size and also taller.  I use an LM317T that has the tab that can be folded down to reduce the height of the board to just over half an inch.  This board also lacks DCS compatibility, so you'd have to add an external choke.  Finally, my design is a constant current design for a very specific reason, it's very easy to get a precise intensity as the adjustment from dim to bright covers the entire pot travel.

Different strokes for different folks.

stan2004 posted:

So with the latest incarnation, the bare per-board cost is down to ~$1.30...and if you do eBay for components, the total out-of-pocket is $2 per board!  Wow.

If you buy a quantity of boards, you can do considerably better than that for this size board.  Here's one estimate, total looks to be around 20 cents a board for quantity 100.

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For those of us running conventional AC, here's another boost-buck unit, similar to what Stan showed earlier, FWIW. 

https://www.ebay.com/itm/DC-DC...047675.c100010.m2109

The one thing it lacks is a trimpot to fine-tune the LED brightness - though I note that these modules seem to come in different flavors, ~3, ~4, 5, 9 and 12 vDC, so doing something at 9v might be an option.  I have the LED strip I've been thinking about using (another one of those "round-tuit" projects) so I could see how bright that strip is at 9 v*.  What caught my eye was the small size - 19 x 14 x 4 mm.  These are $2.85 each, which is a bit pricier than others, but given the number of passenger cars and cabeese I have, affordable.  Still have to have an AC to DC bridge in front of them.

- Rich

*ps  Most of the LED strips I've seen and used (undercabinet lighting in my kitchen) are rated at 12 vDC input -- is there any reason NOT to operate them at a lower input voltage - e.g. 9 v (assuming the light quality is ok at that voltage)?

stan2004 posted:
                                                             **************

....but mate this with a 99-cent (free-shipping from Asia) eBay relay module, set the current to max (45 mA) and for $3 you have an insulated-rail relay module for gate-crossing mechanisms, dual-aspect signals, etc..  Again, this means you must know which end of a soldering iron to hold, but I believe this would be the lowest cost ever for an insulated-rail relay module.  

Okay Stan, where is the eBay link/item number for "99 cent ... relay module" for those of us who do not keep up with this stuff.

You and GRJ are terrific contributors to the content here--THANK YOU BOTH.

richs09 posted:
*ps  Most of the LED strips I've seen and used (undercabinet lighting in my kitchen) are rated at 12 vDC input -- is there any reason NOT to operate them at a lower input voltage - e.g. 9 v (assuming the light quality is ok at that voltage)?

Gosh, no!  Although my modules use constant current, the running voltage of the 12V LED strips actually have from around 8.5V to 11V applied, depending on the current setting.  You don't damage LED's with low current, only with high current!

Pingman posted:
stan2004 posted:
                                                             **************

....but mate this with a 99-cent (free-shipping from Asia) eBay relay module, set the current to max (45 mA) and for $3 you have an insulated-rail relay module for gate-crossing mechanisms, dual-aspect signals, etc..  Again, this means you must know which end of a soldering iron to hold, but I believe this would be the lowest cost ever for an insulated-rail relay module.  

Okay Stan, where is the eBay link/item number for "99 cent ... relay module" for those of us who do not keep up with this stuff.

Dozens of choices on eBay searching for "12V relay module"...such as

ebay 99 cent relay module 12v

The pairing is described in greater detail in this OGR thread which includes a video proof-of-concept.

And as GRJ points out, at higher board quantities the cost is almost unbelievable!  Again, this is for the DIY enthusiast as assembly-wiring-soldering is required.   Though it should be pointed out that off-the-shelf relay modules for insulated rail triggering typically don't have capacitor storage which provides anti-chatter protection and companion inductor for DCS compatibility.

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Need some help.  Ted, did you upload the zip file and then order the boards?  Is there any way to order the boards without loading the zip file?

Thank you,

Gene Anstine

Gene, yes, I uploaded the zip file to Osh Park.  Price is batches of three shipped.  I have an account as I have ordered other boards from them.  I don’t know if GRJ has shared the file or not, but I’m sure he would if need be.  I could share it under my account also, I guess.(but is it mine to share?)  FWIW, I had to use an old windows laptop to upload file.  Copied it to the desktop then within OP’s site pointed the “browse for files” box to that zip.  Was automatic from there.  Really pretty easy.  Couldn’t make it work from the iPad I use for forum work.  Let me know if you need something additional.  Perhaps someone else has help for you also.

Last edited by TedW

Gene, like TedW, I downloaded GRJ's zip file and then uploaded it to OSH Park to order some boards.

Also, after I read your post and TedW's reply, I tried to use the link in his post, and copy and paste the zip file link that GRJ posted.  I had no success in doing this.

As GRJ said, his zip file is safe, and if you want the boards it's an easy way to order them.

And props to TedW for letting me know off forum of the availability of these GRJ/JWA boards.

Now, I'v off to re-read the link in Stan's reply regarding the relays, and then order some on the bay.

Once you have an account set up with OSH Park, it is very easy to do a repeat order or a new order. Uploading John's Gerber files to their site is quite simple. Once the site has processed the files you can see all the front and back views, the silk screening, etc. And they accept Paypal. My first two orders went very smoothly and I had the boards delivered in about 2 weeks.

Rod

Actually I find that the time consuming part of this is ordering all the needed components. John has kindly provided the BOM, but you still need to go to the Digi-Key site and find each component and add it to your cart, then when its all correct go ahead and place your order.

I usually set it all up in a spreadsheet first and I am just working on this for these new boards. If anyone is interested I can post it once complete. Another option would be a snip of my cart summary once complete. I could just post that here for anyone to duplicate. I wonder if its possible to export the electronic cart summary from their site, anyone know?

Rod

Last edited by Rod Stewart

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