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<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial>Hi Quincas,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial>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.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial>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).</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial>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.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial>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.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial>Sorry, that was long, and probably hard to follow. I'll
just email you an example so you can see for yourself.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=905492003-20102016><FONT color=#0000ff
size=2 face=Arial>Dave</FONT></SPAN></DIV><BR>
<BLOCKQUOTE
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dir=ltr>
<DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left>
<HR tabIndex=-1>
<FONT size=2 face=Tahoma><B>From:</B> Quincas Moreira
[mailto:quincas@gmail.com] <BR><B>Sent:</B> Wednesday, October 19, 2016 7:45
PM<BR><B>To:</B> David G Dixon<BR><B>Cc:</B> KA4HJH; sdiy<BR><B>Subject:</B>
Re: [sdiy] PC board from artwork?<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV dir=ltr>David, could you describe how you lay out PCBs in Excel? very
curious :)<BR><BR><BR></DIV>
<DIV class=gmail_extra><BR>
<DIV class=gmail_quote>On Wed, Oct 19, 2016 at 7:36 PM, David G Dixon <SPAN
dir=ltr><<A href="mailto:dixon@mail.ubc.ca"
target=_blank>dixon@mail.ubc.ca</A>></SPAN> wrote:<BR>
<BLOCKQUOTE
style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
class=gmail_quote>Hi Terry,<BR><BR>I can rework the layout to accommodate
more typical quad opamps such as<BR>TL074. This is actually very easy
for me to do. I do it in Excel. With<BR>the graphic and the
schematic from the article, I can reproduce the layout<BR>in Excel very
quickly and then manipulate the layout to change the opamp<BR>pinouts.
No problem.<BR><BR>I could also add some sine shapers if required. I
have a nice design for<BR>sine shapers which I could basically drop onto the
board. It would get a<BR>tiny bit bigger, though.<BR><SPAN
class="im HOEnZb"><BR>> -----Original Message-----<BR>> From:
Synth-diy [mailto:<A
href="mailto:synth-diy-bounces@dropmix.xs4all.nl">synth-diy-bounces@<WBR>dropmix.xs4all.nl</A>]<BR>>
On Behalf Of KA4HJH<BR></SPAN><SPAN class="im HOEnZb">> Sent: Wednesday,
October 19, 2016 4:44 PM<BR>> To: sdiy<BR>> Subject: Re: [sdiy] PC
board from artwork?<BR>><BR>><BR></SPAN>
<DIV class=HOEnZb>
<DIV class=h5>> > On Oct 19, 2016, at 5:57 PM, Byron G.
Jacquot<BR>> <<A
href="mailto:thescum@surfree.com">thescum@surfree.com</A>> wrote:<BR>>
><BR>> > I'd be happy to redraw it in Eagle, and generate
Gerbers,<BR>> if it comes to that. It'd be a quick hour or
so. You'd<BR>> still have to find somewhere to fab 'em - I
typically use<BR>> OSHPark or Advanced Circuits.<BR>> ><BR>>
> It's worth noting that the original design uses 4136's, but<BR>>
might be more useful if they were swapped to the more common<BR>> quad
op-amp package.<BR>><BR>> That was one of the main changes I would
make if, in my dream<BR>> world, I could actually redo the whole thing.
Fortunately I<BR>> have lots of 4136s.<BR>><BR>> The other thing is
that it might be interesting to put sine<BR>> shapers on the oscillators
that form the Lissajous baseline.<BR>> I don't know how it would look
with an ellipse instead of a rhomboid.<BR>><BR>><BR>> > On Oct
19, 2016, at 5:40 PM, David G Dixon<BR>> <<A
href="mailto:dixon@mail.ubc.ca">dixon@mail.ubc.ca</A>> wrote:<BR>>
><BR>> > I would be happy to make one for you, Terry. I make
my own<BR>> boards all<BR>> > the time, and sell quite a few of
them to other hobbyists.<BR>> ><BR>> > I have one or two
questions about the layout graphic, but<BR>> we can deal<BR>> >
with that if you decide you want me to do it.<BR>><BR>> This list is
getting more helpful all the time. I need to get<BR>> past Halloween
before doing anything but after that...<BR>><BR>><BR>> > On Oct
19, 2016, at 5:54 PM, Dave Manley <<A
href="mailto:dlmanley@sonic.net">dlmanley@sonic.net</A>> wrote:<BR>>
><BR>> > Egads, I remember reading that article in my high
school<BR>> library when it was first published.<BR>> ><BR>>
> ObSdiyContent: it must have been about the same time<BR>>
PAiA's 2700 was in Radio-Electronics...<BR>><BR>> Yep, I was a
subscriber when I was in high school. I really<BR>> wanted to build one.
It only took me a couple of decades to<BR>> get around to
it.<BR>><BR>> The dog-eared magazine is in the next room right now.
The pdf<BR>> article on my blog is a recreation of the original, OCRed
and<BR>> reset in the original typeface.<BR>><BR>><BR>> Terry
Bowman, KA4HJH<BR>> "The Mac Doctor"<BR>><BR>>
______________________________<WBR>_________________<BR>> Synth-diy
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clear=all><BR>-- <BR>
<DIV class=gmail_signature data-smartmail="gmail_signature">Quincas
Moreira<BR>Test Pilot at VBrazil Modular</DIV></DIV></BLOCKQUOTE></BODY></HTML>