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Re: Wearable Construction

From: Brian Rankin <>
Date: Mon, 6 Dec 1999 09:36:44 -0800 (PST)

On Sun, 5 Dec 1999, Mark Willis wrote:

> The thing that has to be happening here is huge inductive surges on
> power-up.  BAD news for computer hardware!  I've seen XT/286/386/486
> class machines run off a 12V golf cart battery with some voltage
> regulation and DC-DC voltage converters, for robotics and/or car MP3
> usage (You might look around for the MP3 players, to give that a
> thought.  If you cannot find some, ask & I'll pass you URLs, I'm good
> with search engines.)  Can you get Golf Cart batteries, or other deep
> cycle lead-acid batteries, in Ghana for reasonable prices?  (Marine
> Trolling motors are the same thing, only lots more pricey than Golf Cart
> batteries, you would want deep-cycle batteries, definitely, here.)  Or
> could get them here & ship there.
> 

Deep-cycle batteries are available in Ghana -- that is not a problem.
Based on my experience in Ghana, simplicity is the key to success with
computer technology.  So: if we could build computers that use electricity
from deep-cycle batteries charged with wall power -- that would be the
simplist, most cost-effective solution.   

> 
> Is there an amateur radio service in Ghana?  Could do some kind of
> amateur satellite, we're talking lots of money here though, I think?

Don't know -- though I can find out.

> 
> > Maybe we could begin by working on the specs for the computers to be
> > built. I saw an earlier post indicating that using a Linux interface might
> > be an alternative to Win95.  I think that Linux would be fine, as long as
> > we can make it easy for the children to use (Staroffice instead of MS
> > Office, computer games, etc).
> 
> That could be a good answer.  Need a list of components, and to know
> what way you want to proceed, what the needed resources for each
> computer are, etc.?  What sort of way makes the most sense - you know
> what is needed better than we do!

I'd suggest coming up with a simple computer design that uses minimal
electricity from a deep-cycle battery. Each computer should have
vga and i/o for mouse,kbd,floppy,hd. Hd's can be in an external box.
Ram not <16MB per computer.

> Spare components and "clusters" of identical machines are good, here; 
> What else is needed?  Tie a Linux guru to each machine or something? 
> <G>  (I've been joking about "kidnapping" one local guy to help me with
> a Linux problem, inside joke I guess.  I'll get him to go willingly
> <G>)  I'd guess voltmeters are available at that school, crimp tools for
> Coax for Ethernet (or for 10BaseT?), spare hubs might be good, etc.?

The school has a 16-port hub, and another 8 porter on the way.  They have
crimping tools and a spool of Cat5. I can get spare hubs, etc.  None of
that is an issue.  The key here is designing the hardware so that
components can easily be swapped-out, and so that machines are identical.
Regarding Linux: based on my own experience with RedHat, they may not need
a Linux guru if it is solid enough.  Or, we could go with Win95 as the lab
tech on-site is experienced with that, has training/books, etc.

> A good question for me to ask, too:  What's Ghanan power set for? 
> 110VAC, 220VAC?  50Hz, 60 Hz?  <G>

230VAC, 50Hz

> 
> Would it help if they can e-mail someone in the US who can answer
> questions, and/or hunt down spares and ship them there, as needed,
> perhaps?  I'm not super rich now, but can try to help somewhat.

They do have email. I'm currently providing support, but we could
certainly form a support listserv they could send their questions to.

So: I would say that we should begin by speccing-out the computer design.
I'm not familiar with PC104/sbc options, best practices, etc.  Any
thoughts?

Sincerely,

Brian Rankin

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