[ale] possible meeting topics - ODB / NTP-GPS - And more...

[mhw at WittsEnd.com (Michael H. Warfield)]

As long as we're on the topics of topics...

Based on recent threads, discussions, and presentations...

Robust DNS deployment and management or more.

Grub2 themeing.

Multiboot USB (related to grub2).

I might be able to do one or two of these in the future (just not in the
next couple of months).

I've seen a couple of other threads in the channel that could be
developed into good talks and presos.  We got some good stuff here,
people!

Regards,
Mike

On Sat, 2012-05-26 at 13:47 -0400, Ron Frazier (ALE) wrote:
> Hi all,
> 
> At the risk of opening a big can of worms for myself, I'd like to
> mention two potential meeting topics, which, if there is interest, I'm
> willing to do presentations on.
> 
> The first, which I've put a fair amount of time and energy into, and
> which I've mentioned in a previous thread, is using the OBD (onboard
> diagnostics) system of a car in conjunction with an android tablet to
> display virtual automotive gauges reading the car's vital statistics
> and show the results on the screen of the tablet. This is very cool,
> and, when I mentioned it before, there seemed to be some interest in a
> presentation. The one potential hitch in doing such a presentation, is
> that I cannot bring the car into the classroom. Therefore, I need an
> OBD-II simulator, which I can plug my OBD scanner into, and thus show
> what appears to be live data to the group. I don't know where to get
> such a thing, so, if anyone does, please let me know.
> 
> PS I'm not using the OBD scanner in my car as much as I was. I
> discovered that the MPG estimates, which were one of my primary
> purposes, are extremely inaccurate. You can put a fudge factor in the
> program to compensate, but then you have to measure your MPG the old
> fashioned way first.
> 
> The 2nd thing, which I've invested several months learning about, is
> using NTP with GPS to run my own time server. I am nowhere near an
> expert on the topic, however, I am happy to say that I now have a (non
> public) fully cross platform stratum 1 NTP time server running at my
> house using GPS with PPS as a time source and providing time service
> to the PC's on my LAN. GPS time is maintained by the DOD to within + /
> - 100 ns of UTC as far as I know. So that's + / - .1 us. My time
> server maintains its time to within + / - 30 us or so. The accuracy on
> my NTP clients' side is variable, depending on the load on my wifi,
> and runs from a few ms to a bit more.
> 
> What I'm somewhat proud of, and what was not easy to learn how to do,
> is that I've made everything totally cross platform. The NTP server
> runs and reads the GPS and serves time whether it's booted into
> Windows or Linux, using a different software stack, I might add, but
> still NTP. (Sorry Mac people, I don't have a Mac.) Also, the clients
> access the server whether they are booted into Windows or Linux. Not
> only that, the server may boot on either of two wifi routers I have,
> using two different wifi adapters, and everything still works. That
> presents problems because the server gets different IP addresses from
> the different routers. Getting all these various permutations to work
> was very complicated and tedious.
> 
> As with the OBD stuff, the hitch is caused by the classroom. There is
> no way to get GPS signals in there. So, I need a GPS simulator. If
> anyone knows how to do that, please let me know.
> 
> I did have a thought along those lines. Rather than simulating the
> radio waves the GPS device receives, we could simulate it's output.
> The NMEA output of a GPS is nothing but a bunch of ascii text on a
> serial communications port coming in at typically 9600 baud. The text
> includes coded information strings which specify things like time,
> latitude, longitude, data for satellites being tracked, etc. Suppose
> we were to simply capture all the output from the GPS for a few days
> into a file. If we could create a virtual com port, then we could dump
> the contents of that file into the virtual com port at 9600 baud. The
> NTP program could read the virtual com port, and it would think it's
> attached to a GPS. That could serve as an independent simulated time
> source.
> 
> I see two potential problems. First, the PPS (Pulse Per Second) pulses
> would not be appearing at the DCD line of the virtual com port, and
> therefore, the PPS functionality of NTP would be dormant. Second, the
> time stamps in the recorded data stream would not agree with the rest
> of the world. So, if we let the NTP server communicate with any
> servers in the outside world, it might mark the GPS as a falseticker
> and ignore it.
> 
> Please let me know what you guys think of these topics as
> presentations, and how we might be able to arrange the technology so
> it will work in the classroom. If anyone wants to collaborate with me
> on a joint presentation, I'd be glad to have the help.
> 
> Sincerely,
> 
> Ron
> 
> 
> --
> 
> Sent from my Android Acer A500 tablet with bluetooth keyboard and K-9 Mail.
> Please excuse my potential brevity.
> 
> (To whom it may concern. My email address has changed. Replying to former
> messages prior to 03/31/12 with my personal address will go to the wrong
> address. Please send all personal correspondence to the new address.)
> 
> (PS - If you email me and don't get a quick response, you might want to
> call on the phone. I get about 300 emails per day from alternate energy
> mailing lists and such. I don't always see new email messages very quickly.)
> 
> Ron Frazier
> 770-205-9422 (O) Leave a message.
> linuxdude AT techstarship.com
> 
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-- 
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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