Re: Controllerless distributed automation

["Paul Gordon" <paul_gordon@xxxxxxx>]

Hi David,

>
>I don't think it needs to be that complex, as long as devices are aware
>of _relevant_ neighbours and their status, they don't need (or want)
>complete information.  Would the room stat need to know which TV
channel
>I'm watching?  (OK, having said that, somebody'll come up with a really
>good reason why it might, but you get the idea :-)

That's a fair point, but it does serve to illustrate part of the problem,
who (or what) decides which neighbours are relevent to each other? - if a
room thermostat does not "know" that the actions of a light
switch in the
same room are relevant to it's operation, then might not the heating stay
on
way beyond the time the room has ceased to be occupied? - Actually,
occupancy detection is a really good one to test out any system on, as this
has been discussed at >great< length before, and the groups'
collective
expertise has yet to come up with a failsafe system....But, my point is,
that unless the room thermostat knows the difference between a thermostat
and a light switch, how is it to know that it does not care about that
difference? - with a distributed intelligence system, you have to think
about these things. - any component >must< have a knowledge of it's
environment in order to interact successfully within that environment...




>
>At the moment I'm trying to figure out just what is useful information,
>and what constitutes a "relevant neighbour" before even
starting to
>worry about communications protocols or physical networking.  There's a
>lot to think about....
>

You got that right!


> > (snip)
>
>Erm, I thought you were in favour of distributed systems, or are you
>just playing devil's advocate? :-)  [cf the "Flight of
fantasy" thread]
>

OK, you got me, - you're right, I am broadly in favour of a distributed
intelligence model, but only to a certain point. - I don't yet see the
technology available to implement such a model (at reasonable cost). You're
example (frivolous as it may have been ), of a light switch with 1Ghz CPU
and 128MB RAM, will no doubt be with us one day in the not-too-distant
future, but (and this is the important bit), >NOT< today, and
>NOT< tomorrow
either. (much to my chagrin) (and undoubtedly yours too?)
I would dearly like such a system to be a reality, but unfortunately, it is
a reality only for those fortunate individuals in the lottery winners
enclosure!


> >THIS is exactly what I proposed a month or two ago in the thread I
>started
> >called "flight of fantasy" - I even went as far as to
describe (in loose
> >terms) how such elections could be coordinated and controlled,
with
> >heartbeats, assigned priorities and so on.
>


>I missed/skipped this originally as things were incredibly busy at work
>(lots of late nights) plus I was house hunting at the same time.  I've
>gone back and read all the messages from then, and it looks like I
>missed a lot of interesting discussion.  Unfortunately your doc isn't
>available from the Yahoo archive - any chance you could fire a copy off
>to me?


For sure, - give me a day or three, I'm in the same situation at the mo -
working stupid hours..... (hence I may be rambling incoherently!), but if I
haven't mailed you by Sunday, then please remind me...


>
> >This in my opinion, is actually the better "ideal"
system - any
>objections
> >(which are valid ones, don't get me wrong!) to having a
"single point of
> >failure" are negated by providing redundancy of the central
controller
>role.
>
>The reliability argument is really a minor one.  As you rightly point
>out, these systems are very reliable, and I'd actually expect my
>home-brew bits and pieces to be worse as far as MTBF goes.  It's more
of
>an experiment/research idea really, just to see what might be possible.

Keep up the good work, - 'cos if anyone comes up with a solution, it will
be
a goldmine!!

>
> > (snip)
> >
> >Just my £0.02
>
>Cheers!  Any comments are useful, especially from someone who's been
>thinking about this for longer than I have.
>
>DP
>

It's just a shame that thinking about it is all I have time to do!

Cheers.

Paul G.


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