[sdiy] PC board from artwork?

Fri Oct 21 21:10:54 CEST 2016

No, it's fine.  I know that my methods are a bit "off the grid" but they
work for me.  One thing I like about my layouts is that they pretty much use
as little board real estate as possible in a single-sided board scenario.
Also, my layouts are exceptionally easy to build.  However, the best thing
is that I can have my module up and running while most people are still
waiting for their boards to come back from some fab shop, and the total cost
to me is about $1 per board.

  _____  

From: Quincas Moreira [mailto:quincas at gmail.com] 
Sent: Thursday, October 20, 2016 8:51 PM
To: rsdio at audiobanshee.com
Cc: David G Dixon; sdiy DIY
Subject: Re: [sdiy] PC board from artwork?

Hey you guys, leave Dave alone!  He's a maverick, and a diyer with best
selling designs by a major manufacturer, all while using a spreadsheet
program to design prototype PCBs!  I think he deserves Sunglasses and A
Snoop Dogg soundtrack :D 

On Thu, Oct 20, 2016 at 10:19 PM, <rsdio at audiobanshee.com> wrote:

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 :)
>>

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/
<http://dropmix.xs4all.nl/mailman/listinfo/synth-diy>
mailman/listinfo/synth-diy

-- 

Quincas Moreira
Test Pilot at VBrazil Modular

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20161021/4e23b808/attachment.htm>