[sdiy] PC board from artwork?

[rsdio at audiobanshee.com]

I find it very therapeutic to work on a layout in Eagle. I can spend hours fine-tuning placement of parts and traces.

The nice thing about using a tool is that you can then quickly check your design for the different specifications of various PCB fab houses. I might start by designing to OSHPark's Design Rules, which they provide in Eagle format for download, but then I'll switch to a custom Design Rule file that I've developed while working with Advanced Circuits (4PCB.com). Sometimes, changing the Design Rules will require more work on the layout, which is potentially another opportunity for therapy, depending upon how you look at it and whether there are any deadlines.

Another nice thing about having a tool is that almost nothing is any harder than it really needs to be. That way, the effort is spent on the unique aspects of the project at hand, rather than spending time on the limitations of the tool.

Brian


On Oct 20, 2016, at 5:56 PM, David G Dixon <dixon at mail.ubc.ca> wrote:
> Tom,
>  
> The Excel thing was originally for laying out breadboards.  I hated "improvising breadboards at the workbench" and wanted a tool for laying them out.  After getting fed up with breadboards, I decided that I could also use it to lay out PCBs.  Since I make all my own PCBs in my laundry room basin, I had no need for anything more sophisticated.  Plus, I was able to do pretty decent layouts in fairly short order, and I found it somewhat therapeutic to do so, so that's why I never bothered to learn anything else.  However, lately I've been thinking that I really ought to join the 21st century with this stuff.  I'm taking a sabbatical from teaching in 2017, and will be devoting a lot of time to  synth-DIY activities (including finally learning how to program microcontrollers), so perhaps I'll learn a layout software.  (One thing, though, is that I hate soldering "professionally made" PCBs.  I much prefer soldering my own single-sided boards, even though they often require a fair number of wire jumpers.)
>  
> Cheers, Dave
> 
> From: Tom Wiltshire [mailto:tom at electricdruid.net] 
>> 
>> David,
>> 
>> It's truly remarkable that you put up with such a hideously involved method. I mean, I know how these things evolve, so I completely understand how you got there, but if you stand back and look at what you're doing, given the software that's available, it doesn't make any sense. At the time, you used the tool you had. Then you used the tool you'd used before, and developed it. Before you know it, you're doing full-scale layouts in a tool designed for something completely different, with none of the benefits of a tool designed for the job.
>> 
>> Honestly, try one of the options that have been mentioned. I'd put in a shout in for RS' Designspark too, although maybe they don't have such a presence on your side of the pond. I don't use it (I'm on DipTrace which has already been mentioned, and which I'd also recommend) but I've heard lots of good things from people who do.
>> 
>> Regards,
>> Tom
>> 
>> 
>> On 20 Oct 2016, at 04:40, David G Dixon <dixon at mail.ubc.ca> wrote:
>>> Hi Quincas,
>>>  
>>> I have made a bunch of little graphics in Excel, using just rectangles, lines of various colours, etc, which represent chips, resistors, caps, diodes, etc, with their leads and pins.  The first thing I do is set the grid to 16 x 16 pixels so that the spreadsheet cells are all little squares.  Each square represents 0.1".  Then I select "Snap to Grid" in the Drawing menu so that when I move the parts around they snap to the 0.1" grid.  Then I just do the layout by pure blunt force by carefully working through the schematic.
>>>  
>>> The layouts are facilitated by sticking to a certain basic plan.  The power rails go down the middle of the board from left to right, and all the chips straddle these rails.  Hence, the first row of pads next to the rails accommodate the chip pins.  The next rows of pads are for things that connect between adjacent chip pins, like small stability caps in opamp feedback loops.  The next pads are for components connecting out from the chips, such as resistors and diodes.  These are all 0.4" long, and thereby straddle three potential rows of traces and/or pads.  I call this three-lane conduit the "boulevard" and it is through here that I route signals around the board.  Beyond that is a row of pads for the other end of all the resistors and diodes, and then a row of pads for off-board connectors, and finally a ground trace which typically encircles the entire board.  The boards are arranged symmetrically around the rails.  This means that all of my analog boards are either 2.1" wide, or 4.0" wide for "double-wide" boards (which share a ground trace down the middle between the two halves).
>>>  
>>> Once I've got the layout done, connecting all the parts with different coloured traces (lines with ball ends in Excel), and the layout is reviewed and error-free, then I copy this layout to make several different graphics.  One is "parts-only", one is "traces-only", and one is "pads only".  The "traces-only" graphic is made up of all the traces in the layout, and is made up of several layers of lines.  All traces are made up of three layers of lines, with ball ends of various sizes to make up pads, and smaller lines with small ball-ends on every line to give rounded corners.  Finally, all power and ground traces are copied and made wider than other traces.  These are all consolidated into a single graphic.  The "pads-only" graphic is made up of small circles combined with larger invisible squares to force them to align on the grid.  These small circles sit over the ball ends of the traces, and exist to provide small drill-guide holes for the pads for easy drilling.
>>>  
>>> Finally, the pads and traces are turned black and combined to make the transfer graphic.  This is what is printed and transferred onto the PCB.  Finally finally, the transfer graphic is covered with a semi-transparent white rectangle, and then the "parts-only" graphic is superimposed on this, and that makes the "build pic" which is actually what the completed board will look like.  I use this graphic when I'm stuffing the board.
>>>  
>>> Sorry, that was long, and probably hard to follow.  I'll just email you an example so you can see for yourself.
>>>  
>>> Dave
>>> 
>>> From: Quincas Moreira [mailto:quincas at gmail.com] 
>>> David, could you describe how you lay out PCBs in Excel? very curious :)
>>