Re: Occupancy detection

[Marc_F_Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Wed, 8 Aug 2007 01:30:32 -0400, "Robert Green"
<ROBERT_GREEN1963@xxxxxxxxx> wrote in message
<g7WdnRVnzOL-yCTbnZ2dnUVZ_jydnZ2d@xxxxxxx>:

><ben.parees@xxxxxxxxx> wrote in message
>news:1186161221.507446.92080@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> I'm glad to see this getting attention, because motion activation of
>> lights is definitely on the top of my list of things i'm not happy w/
>> about my automation installation.
>
>It's definitely at the top of my list after I ended up at the bottom of my
>stairs!
>
>> However, reliability doesn't seem to be the issue for me, what is
>> an issue is the latency.
>
>My fall was caused by precisely by the latency problem.

The cost of X-10 wrt oft-needed trouble shooting is well documented. Your
accident was apparently yet another cost.

>The X-10 Hawkeyes were a fine start in selling me on
>the idea of automating lights based on motion detection.  But now the time
>has come for more than simple "on/off based on motion" control.  Large
>stores have triple-redundant opening and closing mechanisms because they've
>been sued so many times they need the additional reliability.  If that's
>where the "state of the art" is, then using just PIR via RF via PC via PLC
>is way far behind.  The light control, at least for dangerous areas like
>stairwells, needs to be as close to instantaneous as possible.  I believe
>that presents just too great a hurdle for X-10 to reliably pass, even with
>the tremendous boost in reliability that Jeff's XTBs have given my system.

I recently installed INSTEON RF and have experienced what INST[antly]ON
means. I can perceive no lag whatever between the time that I press the
button on the hand-held RF remote and the light or scene-full of lights are
on at full brightness.

>The problem, as I see it, is that I still want that light under X-10
>control.

Yup  ;-)

>The reality might just be that in order to do what I want, the
>emergency lighting might well have to be "off the grid" as far as X-10 is
>concerned.  Since a broadcast storm can knock out critical X-10 lightning,
>I'm thinking more and more stairway and other critical lights have to have
>an independent control mechanism that's completely immune to any known X-10
>problems.

One of the virtues of the 'retro' 0-10vdc analog control system I've adopted
is that the control signal can be used to dim low-voltage (nominal 12vdc)
lighting powered from the same central bank of batteries that provides DC
power to the PC's, distribution audio and HA hardware. So in the case of a
power outage, there is no switch over to a UPS -- things, including the
low-voltage track lighting, just keep on running. And because it is
hardwired, it enjoys the intrinsic dependability of that communication mode.

The kitchen and music room ceilings have been wired and the low-voltage track
light installed in the kitchen. Under normal conditions they will serve as
task lighting, ambience/highlighting including artwork. They are powered by
24vdc IN --> variable 0-12vdc OUT power supplies that are controlled by
either DMX512 or a 0-10vdc signal. These are inexpensively purchased,
surplus, commercial DMX dimmers that in their previous life controlled lights
on a floating animated barge in Disney World.

> Ironic, isn't it, that we've both adapted to the limitations of
>the hardware instead of the other way around!    I think that's because the
>first step has been made very easy by X-10.  It takes only 10 minutes to set
>up a fairly sophisticated motion/light control system.  It's the next step -
>improving latency and reliability - that will take a lot of customized work.

Many of us have found that the amusement and benefits we got from X-10
sometimes verged on the masochistic. I don't play hockey or indulge in X-10
any more but have scars from both ...

>> One thing i've considered to help the situation is a product I saw a
>> while ago (sorry no link handy right now) which acts as a whole-house
>> radio reciever and connects to your PC directly.  This would eliminate
>> the "sensors->transceiver->PC" leg of the trip and probably cut the
>> response time in half.  You still have the latency of being noticed by
>> the sensor and the PLC lag time though.  Incidentally this product has
>> a "real" antenna and claims to boost reception ranges significantly.
>> I'm sure Dave Houston knows what i'm talking about and knows whether
>> those claims are valid.
>
>I think that's the WGL "whole house" transceiver, and indeed I acquired two
>products very much like it, but both were unsuccessful.  I live in a wire
>and lathe plaster wall house with lots of steel shelving and other
>impediments to RF.  There was no single place to locate an all-housecode
>transceiver that could "hear" all the transmitters.

With INSTEON RF, you can put an RF receiver in each room and they communicate
over the power lines. No setup is required. Jist plug em in and the
inter-room communication problems go away because transmission through walls
is not required. And no "single place" for a transmitter is needed.

And there are other RF systems that use multiple receivers whose output is
combined by a central PC. Homeseer supports at least one such system that
supports multiple brands of X-10-capable transceivers. See my previous post.

>While it may be working well for you, the bottom line for my situation is
>that PIR via RF just isn't reliable or fast enough.

Some folks are conditioned to what BobbyG writes in the sentence above
because their previous experiences were with X-10 especially  MS12a's
/Hawkeyes and their successors that use a single LHi954 or LHi958 PIR
detector that was designed ~15 years ago!.

Things have progressed in the detector arena.  And RF *is* intrinsically fast
enough (although relayed X-10 RF demonstrably isn't) with actual HA RF
systems for sale that are reliable 'enough' for many folks. Lutron RA, Z-Wave
and Zigbee come to mind. And Real Soon Now -- we can hope -- INSTEON.

>That's why I was
>looking at "beam break" units.  I can't imagine going through a doorway so
>fast that a detector wouldn't "see" the break in the light beam
>transmission.  For that reason alone, IR beams seem to me the most reliable
>of the detection options within a hobbyist's price range.

The motion detector that most often falses in our house is a commercially
installed beam break. Not a panacea at least in our case.

>X-10 and the Hawkeyes were a good start, and I learned an awful lot about
>the "real world" problems of occupancy and motion detection for very little
>money.  But the time has come for a better, more reliable, faster and
>smarter solution.  Or a return to manual light switches!

INSTEON dimmers, whether or not they are being used by an automated system,
look and feel and act just like manual dimmer switches. So they could simply
be "abandoned in place" if one wanted to "return to manual light switches".
This that cannot be said for low-cost X-10. And at <$17 each for INSTEON ICON
dimmers when I bought most of mine, they were less expensive than many manual
decora-style dimmers at Home Despot.

... Marc
Marc_F_Hult
Internet Porch Sale of personal HA and electronic gear at
www.ECOntrol.org/porch_sale