[ale] My Raspberry π is here

Wed Oct 17 13:50:50 EDT 2012

Hi Mike W,

Your message made me think of a specific application for the pi that I have need of.  I have to maintain my Dad's Windows Vista computer.  He lives in Jasper.  I can drive up there to do things and do so periodically.  That also give us the opportunity to have lunch, etc.  However, it's nice to be able to do things by remote control.  I can already do this with a Windows application called CrossLoop, kind of like Go To My PC, etc.  That works OK if Windows is working and all the communications stuff is working.  However, I cannot reboot that way and I cannot manipulate the BIOS.  Dad has to help me get logged into the machine.

I need a fully encrypted remote kvm.  It would sit between the pc and it's monitor, mouse, keyboard, and router; and would, once I'm properly and securely authenticated, transmit all kvm signals back and forth to me.  It should also allow local pass through so the original keyboard, mouse, and monitor still are usable.  That way, I could reboot the machine if necessary, and even get into the BIOS.  Nice to have features would be remote control of the power outlet, status information for the power outlet, remote control of the power and reset buttons, and a visual light signal at his location to indicate when I'm connected.  He should be able to switch off the remote connection at any time if desired, in case anyone nefarious breaches the security.  I may even want a key switch to be turned on at his site to enable login, although being able to log into the machine when he's not even there would be helpful.  The ability to transfer files back and forth would be very helpful.  I suppose I could start Crossloop once I boot up, but that seems a bit kludgy.  The interface between my machine and his needs to be fully graphical without any cooperation from the OS on his system.

I know such things are on the market, but they are quite expensive.

By the way, I like the idea of the power disturbance analyzer.  Available bandwidth may be a problem, depending on what the highest harmonic you want to measure or the shortest spike.  If the sensor pod had it's own micro controller and USB port, you could probably get much higher bandwidth.  It would be interesting to tie some of the sensor pods from the PC based O-Scope products to the pi and run some DSP algorithms or something like matlab on the pi.  I think some of those sensor devices or probe devices use USB.

Sincerely,

Ron

"Michael H. Warfield" <mhw at wittsend.com> wrote:

>On Wed, 2012-10-17 at 10:11 -0400, Derek Atkins wrote:
>> "mike at trausch.us" <mike at trausch.us> writes:
>> 
>> > On 10/16/2012 04:05 PM, Scott Castaline wrote:
>> >> Finally got my π today and wifey wasn't here to grill me, so I'm a
>> >> very happy camper! Happy, happy, happy! Playtime now begins. Even
>the
>> >> FedEx guy has already been playing with one already.
>> >
>> > They are wonderful little things.
>> >
>> > I ordered 5 after last month's meeting so that we could play with
>them,
>> > and I am already looking at putting them to use to solve some
>> > long-standing problems that these are just absolutely perfect for
>solving.
>
>> Okay, what long-standing problems are they absolutely perfect for
>solving?
>
>I can come up with several just off the top of my head.
>
>Easy:
>
>*) A "little black box" with ssh keys, cron, and highly restricted
>access do manage remote server operations and interserver
>communications
>using key auth forwarding over ssh.
>
>*) A security storage module holding CA keys or PGP keys much like a
>smart card might due but higher capacity, higher performance, and lower
>cost.
>
>*) A remote serial console driver to monitor servers.  Sort of an add
>on, out board, server management module.
>
>*) Server monitor.  Drop it on a remote network running nagios and
>health checks against your bigger servers.
>
>*) 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.
>
>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).
>
>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.
>
>You can not measure things outside of the audio range of the device.
>Things like DC offsets and very low frequency that an ADC could measure
>but are generally not of serious concern.
>
>Add another audio input and some induction picks and you could add
>current monitoring.  Another audio input and you can have neutral to
>earth ground (common mode) monitoring.  Some nice beefy batteries can
>keep it going through some long power failures.  With enough on-board
>horsepower to do a decent FFT and you could store large amounts of
>signal data and events.
>
>Yes, I've read the articles indicating that audio input to the RP has
>been less that sterling (sucks?  still?) and may be rather
>problematical.  That's something I really want to test and compare to a
>more general purpose device.
>
>> > 	--- Mike
>
>> -derek
>
>So...  Those are just a few ideas.
>
>Anyone else?
>
>Regards,
>Mike
>
>> -- 
>>        Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
>>        Member, MIT Student Information Processing Board  (SIPB)
>>        URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
>>        warlord at MIT.EDU                        PGP key available
>> 
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--

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