RE: 1-wire advice needed.

["Nigel Giddings" <nigel@xxxxxxxxxxxxxx>]

Piers,



I use the 1-wire temperature sensors in conjunction with a Temp05 board
(now superseded by a Temp08) see www.midondesign.com
<http://www.midondesign.com/> . I
use this with www.homeseer.com
<http://www.homeseer.com/>  there is
a 30 day trial which allows you to
work through some of the abilities...



Personally I have cobbled my systems together from other peoples
solutions rather than building my own from scratch, don't under estimate
the time required....



As far as movement detection and occupancy monitoring you have hit upon
a big area. I am not sure PIRs will do what you want. You have already
mentioned the issue of pets and under sensitivity. Most PIRs are
designed not to give false alarms and therefore err on the side of
caution, or not detecting... Position of the sensors can also be key in
the ability to 'see' movement.



Have you considered using Bluetooth or RFID. Again this is something
that can be used in conjunction with Homeseer and allows the application
to track who is in what location. It does require you to have a
Bluetooth device (Mobile Phone) or RFID tag with you at all times but
depending on your partner this may not be an issue? A lot of this will
also depend on your building, construction type, layout, etc...



Just a couple of more things to consider.





Nigel







-----Original Message-----
From: Piers Kittel [mailto:mailing@xxxxxxx]
Sent: 25 April 2008 18:19
To: ukha_d@xxxxxxx
Subject: [ukha_d] 1-wire advice needed.



Hello all,

Am a newbie, so be gentle :) My English isn't too good, so bear with
me please. I will be happy to share my experience/information with
this list as I go along.

Have decided to start home automation as a hobby (inspired by a
friend) but am currently in the planning stages. I know this stage
will take a long time as I've got lots of things to think through,
after all, I'm doing it all from scratch, including writing my own
controller program. Anyway, I'm planning on using a computer
controlling various stuff around the house, using a 1-wire system to
collect information. Various stuff I want to control include central
heating, lighting, etc. My first stage, obviously, is that I need to
build a sensor network. I won't build the light control system until
much later on, but I'd prefer to get all the sensors every control
system need installed in one go. The sensor network will also include
a few weather sensors (why not?). As far as I can see, the central
heating control system will need a bunch of temperature and occupancy
sensors in each room. This is needed so that the computer can turn
off the rad in a particular room if there's no-one in the room, or if
the room's too warm. The light control system will need a bunch of
light and occupancy sensors - so the computer will turn off the light
in a particular room if there's no-one in the room, or turn on the
light when it gets dark and there's someone in the room.

1-wire temperature sensors are easy so that's one thing out of the
way. My main concern is the light and occupancy sensors.

Light sensor - on Hobby Boards's website, I spot they sell a solar
radiation detector (or more accurately, the CLD140 photodiode) - would
that work as a light sensor in the room? I'd like to be able to
measure the light level - rather than just "Light" or
"Dark" so the
computer system would be able to turn on the light when the room get
dark. Does anyone know what is the resolution of the sensor - what am
trying to ask is whether it can only report whether it's "Light"
or
"Dark" or can it measure how many photons that hits the sensor?
(I'm
only kidding here, but you should see what I'm trying to ask..) Or am
I just being silly, that it'd only work properly outside? If this
sensor isn't suitable for what I need, do anyone know of a better
alternative?

Occupancy sensor - this is a lot more difficult. I know, PIR sensors
did quickly come to mind and there is a 1-wire version of that sold
from Hobby Boards, but my main concern is reliability. I most
certainly don't want the light to go out when I'm still in the room
for example. Another problem is that I have a cat with a mental
illness - she usually sleeps for several hours totally motionless then
for some strange reason, wakes up and immediately shoots out of the
room and runs everywhere at top speed, up and down the stairs several
times and visits all rooms, running around like it's going out of
fashion, and then go straight back to bed, immediately go back to
sleep like she hasn't moved for hours. That is fine and funny, but
not if she causes the system to turn on every light in the house!
What I want to do is for the system to turn on the light in a certain
room if someone is in there and a few criteria is met such as if the
room is dark enough to warrant the light being turned on. Then if the
person leaves the room, a 15 minute timer starts and the light is
turned off if no-one goes back in the room. Is PIR reliable for this
and won't detect the cat? Is there a better occupancy sensor, and is
it possible to link it to the 1-wire system? I brought a burglar
alarm a long while ago with a few dual tech pet proof sensors (link to
sensors below) and never got around to installing the system. Would
the sensors I have be better and am I able to use them? Or is there a
better system I can use instead? I did think a little too far and had
the idea of putting in 2 sensors in the door frame so the system will
know whether someone goes in or out of the room when they break the
beam, but this also could be unreliable. For example, the system
might count 2 people entering a room 5 mins apart, then maybe both
people exit the room close together and so the system think 1 person
left, and assume there's one person in the room, whereas there's
actually no-one in the room. I also don't rather like the idea of
waving my arms every 10 mins to reset the timer. So obviously, this
needs to be nearly 100% reliable, otherwise the WAF will go *right*
down! I do know 100% reliability is impossible, hence the
"nearly"
part.

Thanks very much for your help in advance - much appreciated!

Regards - Piers

* Link to PIR sensors I brought ages ago:
http://www.alertelectrical.com/Burglar-Intruder-Alarm-Systems/Burglar-Al
arm-PIRs-And-Detectors/ADE-Burglar-Alarm-PIR-Detectors/Activ8-DT-Dual-Te
chnology-PIR-8IR110.asp
<http://www.alertelectrical.com/Burglar-Intruder-Alarm-Systems/Burglar-A
larm-PIRs-And-Detectors/ADE-Burglar-Alarm-PIR-Detectors/Activ8-DT-Dual-T
echnology-PIR-8IR110.asp>





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