Firstly - well done - I congratulate you as a man of obvious good
taste and
discretion in your choice of HA system.
To turn to latency - I think that the biggest problem with the X10
PIRs is
that they're not "continuous scan". Instead, they scan the zone every xxx
seconds. Compared to that, the .5 second delay of firing a pair of X-10
messages
round (one from PIR to HV, one from HV to whichever devices you want to
control
as a result) is small.
The most consistently succesfull way of approaching that is to have a
PIR
plug beam break, in conjunction with an HV timer. The beam break plugs into
a HV
input port.
Basically, what happens is as follows:
- If either the beam break or the timer triggers, turn on the
light
- If the beam break triggers, set the timer to 45 seconds, and count
down.
- If the PIR triggers, set the timer to 10 minutes, and count
down.
- When the timer gets to zero, turn the light off.
That means that when someone walks INTO the room, the light comes on
quickly. The trouble is, a beam break can't tell whether it was someone
going in
or coming out... hence it only turns (leaves) the light on for 45 seconds.
... if someone was coming IN, then 45 seconds is plenty of time for
the PIR
to catch them.. and when THAT happens, the timer gets 10 minutes to play
with...
so the PIR only needs to "re-catch" them every 10 minutes.
... if a second person comes into the room, then the timer gets pulled
down
to 45 seconds, but that's STILL plenty of time for the PIR to cut in and
wham it
back to 10 minutes.
... if someone leaves the room, the time gets pulled down to 45
seconds,
but that's STILL plenty of time for another person still in the room to be
caught by the PIR.
... if someone leaves the room, and there's no-one left to trigger the
PIR,
the lights go off 45 seconds later.
Now, in a "destination room", then this is simple, 'cos there's only
only
doorway, and hence only 1 beam break.
In a "circulation room", it's harder, 'cos you need a beam break per
entry.
-----Original Message----- From: Malcolm
Passmoor
[mailto:malcolm.passmoor@xxxxxxx] Sent: Fri 04/10/2002
12:47 To: ukha_d@xxxxxxx Cc: Subject:
[ukha_d] Homevision and PIR's
Hello folks,
Just in case you remember my name from a
previous
posting, I was the chap having some trouble in deciding whether to go for
something like homeseer/cm12u or homevision - well I went for homevision
and
so far I haven't really done much with it - x10 stuff can be quite
expensive
to accumulate!
Any way, my first project is to do the
"movement
in the hall - lights on" thing and I heard some comment that the
wireless
X10 PIR/transceiver set up presents a bit of a lag in terms of response
times
- is this true? To cut a long story short and since I have HV with all of
it
IO capabilities I bought a relatively inexpensive response systems wired PIR - trouble is there are no installation
guide and I'm a bit of an electronics novice - please please
help.
The PIR is a 12v unit so I found a 12v PSU and
connected it the appropriate terminals - its seems to flash when there's
movement so I guess so far so good. I was assuming that I should now
connect
the N/C terminals to port B on the HV to pin and ground - Am I right -
HV''s a
bit pricey and I don't want to try it and fry it. Any help
appreciated.
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