On Mon, May 23, 2011 at 3:43 PM, Denny Esterline <desterline@gmail.com>wrot=
e:

> About a million things :-)
> I would suggest that you start with the understanding that the "perfect"
> design is impossible, then work to "functional".
>

There would be lots of ways to make it functional, but I would like to save
a few square inches on the board, it would save quite a bit of money. Also,
I'm gonna be using these guys: http://www.pcbgeek.com/ and they have a  7x7=
"
restriction. I'd still like to use surface mount parts, mostly.


> First, I see a classic newbie mistake - no mounting holes.
>

My mistake. Thanks for pointing that out.


> You said the autorouter does it "fine", why is that not an acceptable
> solution?
>

It is! I just need to place the components properly. The board will be
operating at low speeds. The microcontroller already has it's own board
(UBW32), and everything else will be running at around 9600 bits/s or less


> You want to "save as much space as possible" - why?  If it physically
> doesn't fit in the mounting location, ok, that's a good reason. If you're
> trying to reduce costs on the board, you need to re-evaluate your motives=
..
> Saving $5 off the PCB on a total production run of three units, compared =
to
> the dozen hours or more it takes to lay out a space optimized version may
> not be your best choice.
>

Difference between 6x6 and 7x7 is 13 sq in. That can mean a $65 difference
if I use Dorkbot, for example. So squeezing everything down a couple of
inches on each dimension would save a lot of money.


> Also consider the future - if you were able to shrink this down to a 2"
> square using the tiniest parts available, how convenient would it be to
> assemble or debug? A little extra space at this stage can make your life =
a
> lot easier later.
>

That's true, but I have no intention of going smaller than I can comfortabl=
y
solder by hand. Someone else pointed out that 1206 size surface mount
components are a good choice, so I'll go with those.
--=20
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