[Hackupy-discuss] USB Chargers

[miloh]

On Sun, Dec 4, 2011 at 2:03 PM, Andy Isaacson <adi at hexapodia.org> wrote:

> On Sun, Dec 04, 2011 at 12:39:20PM -0800, Dana S. wrote:
> > I created a wiki page so folks can share information on their USB
> charging
> > projects:
> >
> > http://hackerspaces.org/wiki/Hackupy/USB_Charger
> >
> > This weekend I put together a USB charger box for OSF (solar driven) and
> > will hopefully get a chance to field test it, do a more thorough write up
> > this week!
>
> We got 4 kits from Tokyo Hackerspace (THS) that I gave to ... Miloh I
> think.  They are built around a neat DC-DC switching regulator that you
> can only get at one particular kiosk in Akihabara, they take 12V input
> and provide regulated 5V on 4 USB ports, with the relevant resistors set
> up so that iPods will charge correctly.
>
> The kits are at Noisebridge and are intended for OccupySF.  I dunno if
> they've been soldered together already or not...
>
>

For anyone else reading, this is the kit from THS that Andy wrote about:
http://taylanayken.wordpress.com/2011/06/25/12v-phone-charger-v2-0/#more-143
Just checked out the schematic and I like it, although I heard the DC-DC
buck converter is difficult to obtain:
http://akizukidenshi.com/catalog/g/gM-02038/  and (PDF link warning!)
http://akizukidenshi.com/download/hrd05003e.pdf

Looks like this DC-DC buck costs $3.87 (300Yen) per part in Japan.

Future modification using a easily sourced (relative to US for us)
replacement part might be a good idea.

I'll get folks to solder them rest of them today (3 parts) at CHM. Can
anyone help with a case design?

It would be great if someone can recommend a good generic case design that
is simple enough to cut in acrylic or wood on the noisebridge laser etcher,
that would provide some mechanical support and basic water resistance.

Captive nuts are a common solution, but not at all moisture repellent.
Plus, it makes the inside a little less accessible. Acrylic glue is another
option, but doesn't allow for easy access into the case.  Any other
thoughts?

-rma
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