On Tue, 2009-01-27 at 18:05 +0000, David Bisset wrote:
> There two significant problems with opening up the schematic files.
> a) The danger that balloon-alikes which aren't in line with the expansion
> plans will dilute the efforts of the few people that have the time,
> resources and expertise to keep this going.
Are there any examples of this in practice?
I don't see how the actions of others, other than potentially damaging
the Balloon reputation, could be detrimental to the original project.
If you're looking at the opportunity cost of people who've decided to
make variants - rather than buying / making a balloon unit.. surely
there are enough benefits for them to work _with_ you without having to
throw up additional technical barriers on an otherwise open design?
> b) The danger of errors creeping into the design.
> This is where Open Hardware is not the same as Open Software because the
> cost of replication is very high, and the time it takes to move a design
> from schematic, to PCB to production to test is very long (in comparison to
> a compile and test cycle on a bit of Open Software), probably a minimum of 6
> months to 12 months especially given that no one is working full time on
> this. (In reality it typically takes 2 years for us to produce an new
> Balloon board when you consider 2-3 prototypes, getting DFM right and
> synching up the software).
What exactly is the extent of Balloon's openness then.. sounds more like
"free as in beer" than free as in freedom from what you're saying. I can
copy Balloon designs royalty free, but the original sources are not
available for people to modify. Surely making these mistakes is a
freedom people might want to be granted?
I requested to join the design group (as suggested by Wookey) so I could
have a stab at converting formats of the closed Altium designs. As an
EDA tool developer (spare time hobby), I'm curious to test our tools
with more complex designs like Balloon. I was specifically interested in
a potential migration path from Altium, and Balloon is the only "open"
design I know of using that tool.
It wasn't that I wanted to open up the schematics (although I don't
personally see that would be a _bad_ thing).
> As I know you are all aware, one small mistake in a schematic can go
> unnoticed until several thousand pounds have been spend making it,
> populating it and testing it. I know this sounds draconian but for these
> reasons iEndian's Balloon boards will continue to be made from closed design
> files (that way, when it breaks, it's our fault...). As we say on the web
> site anyone is welcome to DIY.
If this all come back to the question of supposed liability to the
designers against loss or damage from someone making a variant, then
that makes me very sad. Just because you discourage people making
variants for laudable reasons, it doesn't mean you have to forbid it.
> We are always happy to take design suggestions on board, but we will
> arbitrate and decide what goes down on the boards we make. Partly because we
> already have an idea about how the designs need to progress and because we
> have to make sure that our customers can migrate their products along with
> each iteration.
That is fair enough.. but given a spectrum between closed and open..
there is obviously scope for further flexibility. Those decisions are,
of course, none of my business.
> We will of course publish the designs and make the gerbers available etc as
> we always have.
>
> What *will* be useful is for the external interfaces to be ported to other
> formats so that people can build add-on boards etc.
> I've got a blank expansion board schematic and PCB outline and am in the
> process of making a few connector expansion boards. JTAG done to first rev,
> needs a respin before manufacture, PINKO in progress, SAMOSA ditto, as is a
> double QTE/QSE header that will allow a Balloon and IO board to be
> "spatchcocked". Note also that the "Wired Board" (VGA+Ethernet+USB breakout
> etc) is also at first rev and Peter Long has a CUED expansion board that
> plugs into the Comms connector.
>
> Moving these to a common open design platform would be a good thing.
If you need any assistance, or feature improvements, to make gEDA tools
that open platform, please get in contact. We even have Windows betas
for most of the tools (they don't connect together quite as well
though).
Best regards,
--
Peter Clifton
Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA
Tel: +44 (0)7729 980173 - (No signal in the lab!)
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