From: Spehro Pefhany
Subject: Re: Prototyping 101
X-Newsreader: Forte Agent 1.92/32.572
Date: Tue, 24 Dec 2002 12:18:43 GMT
NNTP-Posting-Date: Tue, 24 Dec 2002 07:18:43 EST
On Sun, 22 Dec 2002 21:40:00 +0000 (UTC), the renowned Joe McElvenney
> So what for you is the normal process (if such a thing
>exists) of morphing between concept and flashing lights?
The procedure varies with the project, requirements and so on, but
here's one recent set of 3 project "breadboards". Nothing was
simulated or breadboarded before going to PCB (just squared paper
and spreadsheets or calculator). All were useful, two of the
three sets would have been shippable had they had solder mask.
The third required more changes, but a working
mockup is complete using it (I'm pushing the envelope on that
design). All 3 required firmware to be written, and all have some
This photo shows the spare set of boards- they are cut apart
before being stuffed.
Combining them reduced the protoyping costs to something
like USD$32 per set including shipping for 2 day delivery.
For small proof-of-concept gadgets, point-to-point wiring
with magnet wire is acceptable for some kinds of circuits,
and can be made fairly compact. It gets very difficult
when the parts get more dense than an SOIC (50 mil spacing).
The cost of PCB prototypes (even multilayer) has fallen
greatly in real terms over recent years (and especially
in terms of engineering time).
"it's the network..." "The Journey is the reward"
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