Re: Cause of some major X10 problems found

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
news:46e75eba.1652704109@xxxxxxxxxxxxxxxx
> "Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote:

<stuff snipped>

> >Actually, I believe that the laws of probability are being very
accurately
> >represented by what we're seeing.  The odds of creating lots of simply
> >random noise are quite high.  The odds of creating noise that the
Monterey
> >reports as BSC's - the right start pattern followed by garbage - are much
> >lower.  The odds of creating a valid code out of random bits are very,
very
> >much lower.  But I don't believe they equal zero and that's based on the
> >reports we see of lone activations in the middle of the night.  Based on
the
> >X-10 propagation speed, and the length of a day, the occurrence rate
might
> >be one in 10,000 or even 100,000.  I feel that sort of "once a day"
> >probability lines up better with the random code generation theory than
the
> >Bloom theory, which should have lights turning on faster than one could
turn
> >them off.
>
> If you mean once every 100,000 years, I agree.

I may have missed it, but I don't see how the "Bloom Theory" can account for
the repeated posts we've seen about stray codes in the middle of the night
or even explain Bruce's situation.  What mechanism would cause a relative
stable source of noise like the PS to flare up at 4AM, as Bruce reported his
"turn ons" occurred, after apparently being unaffected for many hours before
that?  The Bloom theory seems to imply that soon after being exposed to
noise, the susceptible switches would activate.  But that's not what we see.
Previous phantom activation reports tend to match Bruce's, often reporting
that sometime, late at night, random lights come on.

The word "random" was in Bruce's post and a number of others.  That, in my
mind, implies that various switches activate at odd hours in the middle of
the night.  I can't help but believe that reflects the noise source finally
spitting out a code that a switch will react to after spitting out 10s or
100s of thousands of noise bits.  It's the M and J status codes that are
reported most often and, as you point out, those are constructed on the
binary level to be the most likely created by noise bits.  Add to that Dan
Lanciani's comment about some switches not parsing the ones' complement bits
in the right way and those stray activations look more and more like a
reaction to a single code and not some noise spike.

The Bloom model seems to fail when it comes to explaining why it would take
a spike susceptible module 4 or 8 hours to finally succumb to a spike and
turn on.  The "Green" model of random noise finally creating a signal a
switch responds to after 100,000 attempts fits much better with the observed
data.  It's also bolstered by Jeff's observation of two CFL's interacting in
such a way that an X-10 switch could be activated by the bit pattern they
created.

> The fact that grounding the pin fixed the problem rules out that the
switch
> was reacting to some aberrant PLC pattern that would not be reported by an
> X-10 interface.

As I said before, the Bloom model can explain some abhorrent aberrant switch
behavior like your case, but it fails quite fully to explain why switches
would "wait" four or more hours to finally give into the noise that the bad
power supply has been emanating for all that time.  That "magic spike"
scenario sounds even stranger than the "magic created code" one because it
so clearly fails to account for the long delays.

The "Green" theory, on the other hand, explains it nicely because good codes
emanating from a noisy power supply happen very rarely, as one might expect.
Not so rare that they never happen, but rare enough that it takes quite some
time for the noisy PS to create them.

> Nor is there any reason to believe that X-10 would have
> designed switches and modules that responded to patterns that would not be
> reported by interfaces designed by the same people.

There may be no reason to believe it, but I believe Dan L's discovered that
existing switches don't execute the one's complement function for every
slot.  I believe that's your main objection to the possible existence of
these generated codes.  If so, a failure in the error correction detection
HW could allow bad bits to trigger the device anyway.

> Analyze away but count me out - I haven't been on a snipe hunt in over 60
> years.

I can understand why.  If you did happen to find the snipe, you'd have to
eat another avian dish, namely crow.  (-:  No one likes having to do that.
I just watched a program about the man who had captured all the data
required to prove the existence of other planets, but failed to interpret it
correctly before another researcher, looking at the data the first had
posted, was able to make sense of it and prove the existence of other solar
systems with planetary bodies.  Needless to say, he was not a happy camper.

Hopefully Jeff will take up the hunt.  It would be another feather in his
cap to demonstrate that his new XTB-IIR could take such devices in stride
without missing a beat. He also has the smarts and the analytical hardware
to capture any code the power supply might create.  Besides, it would be
nice to prove or disprove the "created code" issue for once and for all, and
in practice, where it counts, rather in theory.  The fact that he's seen
such created codes already when not really looking for them leads to me to
believe that he'll have little problem finding them when that's what he's
searching for specifically.

If Jeff declines, and Bruce agrees, I'll take up the hunt.  If I put the PS
behind a filter with a Monterey and a CM11A so both can log the output AND
add a video camera to record all of the Monterey's readings, I think we'll
see that devices like PS's can indeed create codes that X-10 devices respond
to.  The only potential problem I see is that the PS may have been
interacting with another device in Bruce's house much the same way that Jeff
described the two CFL's interacting to create X-10 like signals and its
behavior will be different on my test bench as a result.  Even if that's the
case, I have some very noisy CFL's that might be used to "beat" against the
noise signal from the power supply.

--
Bobby G.