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chadbag

JNSF DIY lighting project (PCB based)

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chadbag
28 minutes ago, gavino200 said:

 

The goal has been to make the strip as universal as possible. A caveat is that they don't have a direct connection to the pick up strips of a coach. A small length of wire will be needed to connect the LED strip to the car's pickup strip. 

 

It should be possible to buy brass strips and bend them (and solder to the input pads) such that you can fit them in a KATO wagon, theoretically speaking.  I have not tried it.  I may as an exercise (I don't like to notbe able to do things I think should be able to be done 🙂 ).

 

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chadbag

With regards to the V2.  I ordered some breadboards, jumpers, and non-SMD component assortments for caps and resistors, and i already have a  bunch of normal LEDs, so I will be able to test the V2 circuit more easily than soldering it up using wire.

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cteno4
58 minutes ago, gavino200 said:

 

How small is the pot that you're thinking of? It needs to be very small in order to not obstruct or be visible. 

 

3.1 x 3.8 x 1.6 mm so below the height of other components

 

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Soldering an SMD resistor is seriously not difficult. They're minuscule and close to 100% reliable. 

 

For all intensive purposes a variable is as well in this case

 

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That's not a bad idea. Is that what you were talking about earlier? I thought you were considering incorporating a pot into the circuitry of the LED strip. If you're just talking about using a pot to decide on the value of the dimming resistor then we're in complete agreement. In fact it doesn't even need to be an SMD pot. You can use a larger one and rig up a little test board.

 

Both. Use an external one to set your resistance for the light needed then just set it on your boards with the pot instead of a fixed resistor. Can the easily be changed if needed later. One size fits all.

 

whrn ever I’ve played with scale lighting it’s been a lot of fiddling to get it looking right and so I’ve gone down the path on structures to always use pots to allow a lot of fiddling at any point. I am going to experiment moving that into car lighting when I go there for sure.

 

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It's unnecessary. I really don't think it adds anything. I am however impressed that Chad can pull it off

 

Switch can be added to the board and you just add it and two different resisor values or single resistor and no switch. If he wants it there its just the path design to make it so.

 

i can see why they did it on the poppendetta boards as you are buying it all made up so they wanted to give two light levels to use instead of just one.

 

jeff

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Ochanomizu

Hello,

 

Thanks for the responses to my last post.  I must admit, overnight the penny dropped and I realised the price was for unpopulated boards.  Can you obtain a price for complete boards with components?  I'm not keen on soldering up 1500 boards ... I'd prefer to purchase completed boards, I think.

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chadbag
4 minutes ago, Ochanomizu said:

Hello,

 

Thanks for the responses to my last post.  I must admit, overnight the penny dropped and I realised the price was for unpopulated boards.  Can you obtain a price for complete boards with components?  I'm not keen on soldering up 1500 boards ... I'd prefer to purchase completed boards, I think.

 

I don't know where to look for completed boards, but I would guess it would be a bit more.  I've been researching and using the so-called "hot plate" method, it should go pretty fast to solder up the boards.

 

You can google "hot plate smd" and find a bunch of articles and videos on it.  Basically, your typical portable hot-plate is used to heat the PCB up to hot enough to melt low temp solder paste.  So you apply low-temp solder paste to each board (using a syringe or template), place all the elements, and stick it on the hot plate until the solder melts and flows.

 

 

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cteno4

It’s the frying pan method! I saw that a few years ago and meant to try it. Don’t have to worry about components moving and can do a number of boards at once. Small oven is a couple hundred bucks.

 

Im guessing 1500 would be the beginning of getting a very small commercial run. China or India. From the numbers I remeber Ardesh was doing with pcb work it was starting around that number in India and China.

 

Jeff

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Ochanomizu

Hello Mr chadbag,

 

I found a China manufacturer: www.pcbway.com

 

Could you check it out?  I tried their instant quote based on your V2 schematic.  I may have answered some of the questions incorrectly, but 8000 units appears to be around $2000.

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Martijn Meerts

I have soldering tweezers, great for SMD stuff.

 

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chadbag
6 hours ago, Ochanomizu said:

Hello Mr chadbag,

 

I found a China manufacturer: www.pcbway.com

 

Could you check it out?  I tried their instant quote based on your V2 schematic.  I may have answered some of the questions incorrectly, but 8000 units appears to be around $2000.


I'm looking at it.  Once I get the V2 layed out, I'll upload it there and put in some numbers and see what they give us for assembly quote (and PCB manufacture). 

 

They are similar to the place I am getting the V1 boards done (which claims to be the largest PCB prototype and small batch manufacturer) but the place I am using now does not do assembly.

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gavino200
cteno4

No I think he is referring to this kind of soldering tweezers. Basically tweezers with soldering iron tips at each end.

 

https://www.qsource.com/itemdetail/?itemCode=PA120-A-J006&gclid=EAIaIQobChMImaDzy8uT4QIVTQOGCh1F0Q9pEAQYBCABEgIAfPD_BwE

 

you can heat bit sides of a smd component at once. At times it can be hard to desolder both sides of a part if you can’t get a rework blower in place to heat both sides evenly or need to keep heat localized. Does require a very steady hand with small smd bits. Probably a lot faster with a rework blower to put down a lot at once. Rework blowers can move parts around some so again it can be handy in tight spaces and not heat up and reflow the component next to one you are putting down. Most good rework station have these as an optional iron attachment in place of the single tip lead and are not as expensive as all in ones.

 

Pjeff

 

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gavino200

Wow!! I want !!

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Martijn Meerts

I did mean something like Jeff linked yes. The soldering station I have I bought as a set. It’s a digital one with very fine temperature control and has 2 outputs. One for the included micro soldering pen, the other for the included soldering tweezers. Of course, you can also hook up other items, I have a higher powered soldering iron as well for example. 

 

I use use the tweezers mainly for desoldering and replacing SMD components. On new boards I generally use the soldering pen and just solder 1 side of the SMD component at a time, but it’s quite possible to do so with the tweezers as well. The tweezers are also great for removing non SMD LEDs from a light board, since you can easily heat both legs at the same time. 

 

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gavino200

This is what you have Martijn? It looks great. Desoldering is a pain. Usually I have to go over and back a few times before I get a component fully desoldered. Also I had a radioshack pencil iron, but it was very low voltage. I think you're exact set is discontinued, but I think I'll get a system like this. Probably a suitable birthday present. 

 

 https://www.jensentools.com/weller-wd2000m-rework-station-with-micro-soldering-iron-micro-tweezers/p/441-861

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Martijn Meerts

That’s the one yes. Was quite an investment but soldering is now no problem rather than one of the most annoying things of model railroading. It also heats up real fast (3 seconds to get to 350 degrees) and the tips can be swapped even when they’re still hot, since the heating element is part of the tip itself. 

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chadbag

The V1 boards are listed as "Waiting for carrier pickup".  Since I specified DHL, I should probably see them Monday, assuming they get picked up reasonably.

 

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