Can anyone tell me how to re-layout a board in KiCAD?

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Mbira

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Jun 4, 2004
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Austin, TX
I'm building a project where the layout and schematic, etc, are in KiCAD.  I want to change the board dimensions to be bigger and make the traces bigger (easier for home etch), but I want the footprint of all the components on the board to stay the same (but they can move around obviously).  Driving myself nuts in photoshop and just want this done...can anyone tell me how to do this?  Thanks!
 
You have very basic questions and I think you need something like Kicad Tutorial or Kicad User's Guide. The board size can be changed by changing the active layer to PCB_Edges and moving the board edges or removing the old board frame and drawing it from scratch. Changing track width is slightly more complex but if you google for "Kicad changing track width", you will find it. It may be required that you have all the libraries used in the design but maybe they are included in the project. Components can be moved on the board simply by clicking on a component and selecting "Move" from the right-click popup menu. Or you can just type "M" on the keyboard.

Mark
 
do you have the project files? at least the .net and .brd files? You can change the track widths by doing to the design rules window. For home etch with plenty of space I go with .03 track width.
 
Just saw you other thread...I DL'd the files, will take a look now.

****For that layout, your trace width is pretty much maxed out, the traces on the left side are as close together as they could be, any closer and home etching would run the risk of bridges between traces.

If you made the board bigger, then spread the components out, you'd still have to redraw the traces manually. you can drag components with their trace connections intact by pressing G over the component, but then you still have to redraw them because they'll overlap other traces. This is not simple tweaking, this is a major surgery, it's gonna take some hours. The only other option is to move the components to where you want them, then clear the traces completely and use the java autorouter feature, which works really well, I might add. The only problem with that is that it will only do two layer minimum, so it will route on the top layer as much as the bottom, meaning double sided home etch, which is still doable, but a few more steps.

So, ask yourself, do you NEED to do this? What's stopping you from etching it as is? Looks pretty good to me!
 
I also checked the project. The schematic displays message box about several missing libraries but the board opens without any problems. I understand that you would like to manufacture the board at home but why? It will cost you 30-40$ manufactured by professional company while enlarging the board will take a week or so (especially if you are not experienced with KiCad). I think that you can also buy the board (even with programmed processors) from megadrum.info.
The board is designed correctly and it would be a waste of time and money trying to enlarge it. 

Mark
 
I say you can home etch as it is, if you wanted to. the top layer is pretty minimal, so you could jumper those traces with small wire, and I believe this design enables you to program the PIC onboard, without a separate programmer. I've been looking at this project myself for a while.
 
I'm out of practice with home-etching and I've already wasted two boards trying to do this one.  The traces seem too close together for my skills at this time, but I'll try again :).

I was hoping there was an easy way to:

Change the size of the board to a bigger size
Set the minimum dimensions of the traces
Have KiCAD re-autoroute the board

and be done with it...
 
Well there's a lot of work between now and "being done with it"... but it's doable. The only thing is that you can't make the IC pins and further apart, so how ill making the traces further apart help you any? ***EDIT: also, the traces that run between the pin of P1 connector can't be rerouted, there's realy nowhere else for them to go without a major re-design of the board, OR doing a top layer...(again, not home-etch friendly) I suggest figuring out what's going wrong with your etches, as this is something that needs to be done right, no matter how tight the traces are.

OR...

http://www.megadrum.info/content/buy-synthexs-megadrum-kits
 
Synthex kits have not been available for a while.  I am building the 56 channel version.  I have already built a 32 channel version.  There is no one that is selling boards for this version.  In any case, I'm not really into buying kits or boards from others if I can help it as this is after all DIY. :)

RE: P1, I already did most of that work in photoshop, I just moved back the ground plane, and did several jumpers.  Tedious, but very doable.  There are several jumpers already used on the board, so I figured it was an easy task to tell KiCAD this is a single sided board and to use jumpers if needed.  Sounds like I was wrong.  In any case, I got a couple more boards, and I will try again this evening.

RE programming-unfortunately, the designer has decided that he wants to keep his more recent firmware versions closed-source, so the only way to get an atmega programmed is through him-either by buying a chip directly, or by sending him one to burn. 
 
Incidentally-I tried again and had good success with all my boards.  I got my timing right again, and in the past, I had doubled up the pieces of velum paper when exposing the boards, but with these small traces, I was getting blur that way.  Much better results tonight.
 
I had doubled up the pieces of velum paper when exposing the boards, but with these small traces, I was getting blur that way

I even triple them. And i use transparent paper as well, "Steadler" laser paper, not a very nice transparency but it works good.

And for blurred small traces, that's because you really have to put a lot of flat weight on the board while exposing, light tends to pass underneath and that's why.
Better to have the printed side on the Photoresist as well, i had some weird things when done the other side, but that's just me... 
Over-exposing will also make those tiny traces disappear on the board, got to find the right timing for them as well.
Well if tiny traces are less than 0.3mm...
 
I switched to vellum years ago and never went back to transparencies.  It's much easier to get a solid black on the vellum because the ink sticks better.

If you consider that the ink side needs to be right up against the board, then it makes sense that as you double (or triple) the number of sheets, you will get more blur.  I don't think it's just an issue of light getting between the board and the paper, but it's also an issue of the angle of the light as it hits the board.

In any case, one piece of vellum taped to the board so it had a good tight fit and 2 minutes in my box worked great.  I still think the pads on this particular board are too small for good home-etch, but it'll do.
 
I use two pieces of glass, a book of my daughters , the lid of my black light box, and an mbira on top of that. :)
 
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