[conspire] Risks of automation

[Denny Yang]

Hi Rick

Hope you have been doing well.

Can you please tell me which one, or two of these open source
application(s)
is / are suitable for Linux newbie?

If I don't ended up using it, I know at Least how to install it.

- Fresh
- Bugzilla
- DokuWiki
- Drupal
- Etherpad Lite
- Gitlab
- Joomla
- MediaWiki
- Moodle
- osTicket
- OwnCloud
- phpBB
- PunBB
- Redmine
- ServiceDesk Plus
- SugarCRM
- Trac
- TWiki
- WordPress
- Zen Cart


Thank you so much,
Denny

On Thu, Aug 16, 2018 at 3:53 PM Rick Moen <rick at linuxmafia.com> wrote:

> I recently dealt with a perplexing diagnostic problem, which I tackled
> stupidly for a few days, and then on account of being suddenly cluebatted
> solved it.  Even though this has little to do with Linux, I think the
> story may be of interest.
>
> This is also a cautionary tale about the downside of automation:
> Automation when it fails will cheerfully, quietly, and efficiently kick
> us in the shins, every time.
>
> For those who haven't been here, my family lives on a large, 1/3 acre
> lot in West Menlo Park, my childhood home.  Since moving back in 2006,
> I've reclaimed much of the lot from wildness, have a large vegetable
> garden, and are growing many fruit trees.  As California's drought
> developed, though, and we were suddenly put under water rationing a
> couple of years back, I realised that our haphazard maze of soaker hoses
> would never do.  In a huge rush, I replaced those with a drip irrigation
> system.  Cutting corners to save time, I put all of the side and back
> yards (except the rear lawn) on a single watering run.  The second
> watering run is the front yard, and the third (of three) is the back
> lawn.  All three watering runs are turned off and on by standard 24VDC
> solenoid valves.
>
> The crowning piece of the system was/is an Arduino-based watering
> controller with open-source firmware, OpenSprinkler
> (https://opensprinkler.com/).  Arduino boards are very basic, very
> low-power computers, not intelligent enough to run Linux, but extremely
> suitable for controlling analogue devices such as watering systems (and
> many more things).  OpenSprinkler packages an Arduino board in a neat
> plastic enclosure with LCD display and control buttons, with connectors
> for 24VDC to control standard watering systems.  You communicate from a
> real computer to your OpenSprinkler's admin WebUI to set up when and how
> much to water on each connected run, and to configure optional features
> like one where it gets weather reports from commercial site Weather
> Underground and uses that information to lengthen or shorten watering
> duration.  It's all really cool -- and invites setting and forgetting.
> It's been working beautifully for some years, and among other things
> seemed to end the depressing syndrome of plants dying because a member
> of my family promised to water them and then flaked out.
>
> The latest filip added to the system was a rain detector, which is just
> a cheap plastic gadget you mount on the edge of your roof that collects
> a sample of rainfall when it occurs and alters the state (on or off,
> i.e., closed circuit or open) of its long 24VDC wire back to the
> controller computer -- signaling either 'it's rained recently' or 'sure
> is dry lately'.  This rain detector is a bog-standard Rainbird unit from
> Home Depot.  Specifically:
> https://www.homedepot.com/p/Rain-Bird-Wired-Rain-Sensor-CPRSDBEX/203829203
>
> A rain detector accessory helps prevent the absurdity of automated
> watering persisting during the November-April rains, so it's A Good Thing
> -- isn't it?
>
> The above sets the scene:  Automation: yay.   Because consistent
> watering gives better plant growth, less accidental plant murdering.
>
>
>
> About the end of July, both my mother-in-law Cheryl and I noticed that
> two trees in the back yard were suddenly looking shockingly parched, a
> fig tree and a calamansi tree.  This was very puzzling because they were
> established, several-year-old trees that had been doing well.  Also, in
> the side yard just outside the cross-fence, a hydrangea was suffering
> badly, and a nearby fern looked as if it might be dead.
>
> I was also vaguely aware that a plant in my front yard was dropping
> badly and one in a pot on my front porch (Helichrysum petiolare aka
> licorice plant) appeared to be suddenly dead.  These were on a separate
> watering run from the others, which would have been a big, fat clue if
> I'd stopped to think clearly.  Also, the spearmint plant on the back
> porch seemed to be dying back, which seemed really odd, because hardly
> anything can bother a mint plant.
>
> Because one of the rules about diagnosis is:  distrust coincidence.
> It's much more common for there to be a signle underlying cause of a
> problem, rather than two different things suddenly going wrong at the
> same time.
>
> _Failing_ to apply that rule, I fell back on Drip Irrigation 101,
> concentrating on the distressed or dying plants/trees in the back.
> First, I checked that the drip-irrigation emitters weren't clogged,
> which one does by running a manual watering sesion for that run, and
> then making sure water is dripping out.  I also started unburying the
> main drip irrigation runs from accumulated leaves and debris, and
> checking from end to end, to make sure silt hadn't infiltrated the
> watering system and clogged things.  Every time I started manual
> watering, water was duly being delivered everywhere.
>
> I also got out a bucket and watered the distressed plants/trees twice a
> day, since _something_ was obviously going wrong, and it seemed to
> involve shortage of water, maybe, so pouring some around their rootballs
> appeared to be a good idea.
>
> Cheryl urged me to double the watering times everywhere.  I resisted
> this notion for a couple of reasons.  (1) Cheryl notoriously always
> wants to increase the water to any plant in any kind of distress without
> bothering to determine whether that is useful.  (2) Finally, I started
> applying systems-level logic, what is crucial to diagnosis:  _Why_ would
> there be a sudden need for a lot more water?  This summer wasn't hotter
> and drier than last year's.  If anything, it was less so.
>
> (Around this time, Cheryl, to give hear credit, pointed out that the
> rear yard's lawn was looking parched.  I shrugged at the time, replying
> that it was normal in California for a not-very-good antique lawn to
> look bad in the hot days of summer, and that I didn't want to waste
> water on this one looking green and lush, going into August.)
>
> Suddenly, I thought about the larger problem:  If not a lot-wide summer
> need for greater water, then what would account for all this?  Any
> solution would need to explain problems on two separate watering runs,
> three if you include the lawn.  I wasn't coming up with a qualifying
> hypothesis.  The fact that manual watering sessions consistently worked
> fine seemed to create a baffling set of facts.  The notion of _manual_
> watering working great, but _automatic_ watering being disabled in error
> didn't occur to me.  After all, automation yay.
>
> I was stumped for several more days.  Every time I tested the watering
> system (with a manual session), it worked.  So, it was fine -- wasn't
> it?
>
> Then, I was logging into my OpenSprinkler admin webUI yet again, and
> this time I looked more closely.  On the main screen was a small
> ribbon banner, red, with the text 'Rain detected'.  Um, whoops?  In
> early August?  Near Stanford?  Something was very wrong.
>
> I tilted the rain detector gadget down.  Had it somehow, in early
> August, gotten clogged with something wet?  Nope.  Dry.
>
> Refreshing my memory about such things, I remembered that rain detector
> widgets work in either of two ways:  Either detected rain causes them to
> _open_ the 24VDC circuit (no current allowed to flow) or _closes_ the
> circut (current flows).  The widget's package specifies which mode of
> operation applies, and when you connect it to the controller (such as my
> Arduino-based OpenSprinkler), you configure the latter to know whether
> the detector's going to say 'open' for rain or 'closed' for rain.
>
> Before really thinking that through, I experimentally disconnected the
> rain detector from its terminal on OpenSprinkler, and rebooted
> OpenSprinkler.  From my laptop, I logged back into the admin webUI.
> The red 'Rain detected' banner was still there.  WTF?  Oh, right.  This
> rain detector was one of the 'set an open circuit to indicate recent
> rain' variety.  Therefore, if you simply disconnect the rain detector,
> but don't also update OpenSprinkler's settings to say 'You no longer
> have a rain detector', naturally OpenSprinkler will think it's raining,
> because nothing connected == open circuit.
>
> I disabled the OpenSprinkler setting for 'You have a rain detector'.
> The red 'Rain detected' warning banner went away.
>
> Damn, I thought:  Obviously, the rain detector's circuitry failed
> in such a way that it got stuck showing an open circuit, the device's
> corpse inadvertently lying and saying 'It's still raining.'  Wow, that's
> the worst possible hardware failure mode.  I should have bought the
> other type of rain detector, I thought.  But then, I realised that
> _either_ type of detector could die in a way that makes it false claim
> it's always raining.  The other type could die in a permanently
> closed-circuit position.
>
> The problem with reliable operation is that you tend to rely on it.
> For a long time, I'd had no reason to login to the admin webUI:  Why
> should I?  The weather-responding automated watering was working
> beautifilly.  The parts of the system I _did_ spend time worrying about
> were the mechanical bits: leaks cause by rodents' knawing, clogged or
> detached drip emitters, places I'd stupidly nicked a water feed pipe
> with a shove, that sort of thing.
>
> If I _had_ looked in the admin webUI, I'd maybe have noticed the red
> thin banner at page bottom -- or looked at the device logs and seen that
> sessions kept being skipped in late July on account of rain.  But I
> hadn't, because automation yay.
>
>
> The losses:
>
> o  We're pretty sure the calamansi tree's a goner -- the worst of this
>    calamity.
> o  Same with the fern.
> o  And the licorice plant on the front porch pretty clearly isn't coming
>    back, even though that species is drought tolerant.
> o  The other plant in the front yard (which is planted in the ground)
>    recovered.
> o  The fig tree is showing ongoing small signs of life, e.g., the buds
>    at the ends of branches are active, even though the tree lost all
>    leaves (as did the calamansi).
> o  The spearmint is springing back.
> o  The lawn looks greener.
>
> Rainbird's $23 + tax junky little plastic rain sensor failing in the
> worst possible way at the worst time of year cost me a treasured fruit
> tree and a couple of nice plants -- because I relied on it, relied
> on the automation, and didn't check.
>
>
> And I re-learned that, when you're trying to diagnose a problem, you
> need to stop and collect all the symptoms, and not be happy with a
> candidate explanation unless it can explain them.  All of them.
>
> As with diagnosis of computer hardware or software problems, expertise
> is not actually required.  Observation and carefully keeping track _is_,
> as is consistent use of logic.  Those alone can pretty much always reach
> the right answer.
>
>
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