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HI All
>As I am about to add new heating and cooling to my house... I would *love*
>to know how this was done!
>
>Cheers,
>Jeff Rafter
Several years ago I worked for a company that installed heating,
cooling and electrical systems in Office Buildings. These systems were
design with the use of
remote sensor
- Heat sensing to determine inside room temperature and
outside temperature
- Humidity sensing to room humidity
- Pressure sensing in heating and cooling ducts to determine
- if fans were on or off
- if filters were clogged with dirt needing
replacement
- Water sensing in areas where it shouldn't be
- Door / window sensing for security and heating control.
- Electrical current sensing
- to determine on and off state of electrical or
electronic devices
- to determine malfunctioning devices
- Light sensing
- Motion sensing
- entry access readers
- Others
Remote Controls
- Switches
- Servo motors
- Electronic Locks
- Others
These were all wired together via a RS232 interface to a computer
system that monitored the state of all the devices and made adjustments to
the system accordingly. The software stored the information in a tabular
database which could be used to generate reports and control the system.
1) If the office was closed at 5:00 pm and on week ends, the system
would turn the heat down, turn off lights in rooms that were not occupied
and inform the security guard if a room was occupied that shouldn't be.
2) If the Office opened at 8:00 the heat would be turned on at a
specific time, Earlier if the outside temperature was say 20 degrees, later
if it was 60 degrees. because the system over time kept track of how long it
took to return the rooms to a comfortable level for the particular occupant.
3) Some of these systems even monitored the temperature of
electrical devices like lights and motors and when the temperature is high
enough, will pull the heat off the device and into the heating system.
Today, instead of wiring everything together, these systems use
Digital remote control access. Some use the buildings electrical system as a
giant antenna to send an receive information wirelessly.
Here is Web site that has some information.
http://www.attr.com/monitor/index.htm
Radio Shack sold similar systems for home use.
There are some contractors to day that build homes with theses
systems in them (Smart Homes)
The system I have is home grown. I have base board electric heat
with a thermostat in each room. I modified these with digital transmitters
similar to the ones used to open car or garage doors. Radio shack has kits
you can buy. I can set individual room temperatures from the Thermostats
that report the change back to my computer system, or from the computer
system.
The computer system has software that monitors the signals, converts
the signals to ASCII data, wraps it with XML tags based on the content and
passed it to a parser that acts on the information, turning on or off the
heat/cooling based on the Current State XML. XSLT is used to Convert
information in the Device Information XML to the required binary signals for
that device. A PERL Script did this at one time but I thought it would be
nice to change it to XSLT as a learning experience.
<Heating:Device type="thermostat" address="device-address" io="input">
<!-- io =
"input" to the computer system
"output" to the device
-->
<State-Change type="setting" time="yyymmddhhmms"
operator="manual">72.2</State-Change>
<!-- Thermostat was manually set to 72.2 degrees -->
<!-- type=
"setting" to change the thermostat setting
"temperature" when the thermostat is reporting a change in the
current room temperature
operator=
"manual" setting was changed manually at the thermostat
"system" setting is changed by the computer system
"keyboard" setting is changed from the system keyboard
"remote" setting is change remotely from a TV remote control
if "remote" this element will contain an address attribute
containing the address of the remote device.
-->
</Heating:Device>
Basically all I did was modify the control software to manage the
data as XML rather then the tabular database it was managed in. It is easier
to read then the binary data.
Thanks
Bill Conrad
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