[ale] My Raspberry π is here

[Michael H. Warfield]

On Wed, 2012-10-17 at 16:17 -0400, mike at trausch.us wrote:
> On 10/17/2012 11:06 AM, Michael H. Warfield wrote:
> > *) A remote serial console driver to monitor servers.  Sort of an add
> > on, out board, server management module.

> Would that not require additional hardware to convert from 5V to 3.3V?

I think we're mixing apples and oranges and probably my fault.

Yes, it needs additional hardware, specifically a USB to serial UART
adapter (cheap - I've got fistfuls of those babies).  That's not 5V to
3.3V.  That's more like +- 12V RS-232 to USB.  I didn't literally mean
that you could drop a RP into a chasis in place of a server management
module.

> > *) Server monitor.  Drop it on a remote network running nagios and
> > health checks against your bigger servers.

> Oooh!  Slave monitors capable of monitoring on the LAN when the World
> Wide Pipe disappears, and can check in with a master monitoring server!

Yup...

> > *) Logging server.  Have it running rsyslogd and just saving syslog
> > events off the local network to the SD card where it can't be tampered
> > with by intruders who can't reach it.

> YES!  I had that idea a couple weeks ago for a client office.  Swap the
> devices out when they start getting full, and a great way to then be
> able to control how things get archived.

Or have ET occasionally phone home and upload the stored logs when they
are archived.  Works either way or both.

> > Because they're cheap, you can use lots of them as embedded controller
> > devices for for small specialized tasks like these.
> > 
> > A much more difficult straw man idea I've been wrestling with:
> > 
> > (This one I believe Mike T will relate to immediate based on some of our
> > recent discussions...)
> >
> > How about a DIY power line disturbance analyzer?  Take your AC power
> > line signal (both phases) and divide it WAY down (say 1000:1) so it fits
> > within range of an audio signal.  If you're not really concerned too
> > much, some nice resisters will do along with some micro-fuses and
> > transorbs.  If you are paranoid about playing with high voltage, some
> > linear opto-isolators are even better, just more complicated.  Now feed
> > those two signals to the stereo input of a USB audio adapter.  It's just
> > a 60Hz signal, after all, with the two phases 180 degrees out of phase.
> > Most ADC (analog to digital converter) daughter boards I'm seeing for
> > the RP are two slow for what I want (15 samples per second for a 16 bit
> > 8 channel board is NOT going to hack it).

> Can we build it?  Can we build it?  Please?  :-)

I'm going to start testing some design ideas as soon as I get the
components.

> > Now you can monitor and measure things like...
> > 
> > * Surges
> > * Sags
> > * Spikes
> > * Dropouts
> > * High frequency noise (notch for X10 and Insteon if desired)
> > * Frequency
> > * Voltage
> > * THD (Third-order Harmonic Distortion)
> > * Imbalances
> > 
> > Basically the things that a decent line disturbance analyzer does only
> > without the $10,000 price tag.  Commercial units I've worked with will
> > handle more phases and more inputs at higher voltages, are hipot (hi
> > potential) tested and isolated for workplace safety, and are often
> > calibrated and tracible back to NIST standards, which are not
> > necessarily things we need (hipot isolation is desirable to protect the
> > device but may not be necessary as a safety feature do to more limited
> > voltages in the home).  That could be in the price range where you
> > install it near your breaker panel and just leave it there and download
> > data occasionally.

> Can we install it?  Please?  :-D

After I get mine installed...  :-)=)

Mike
-- 
Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
   NIC whois: MHW9          | An optimist believes we live in the best of all
 PGP Key: 0x674627FF        | possible worlds.  A pessimist is sure of it!
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