What Infrastruture? - newbie question

["semi.jons" <semi.jon@xxxxxxxxxxxxx>]

Hello!
Like many of the newbie questioners on HA groups on the net I am=20
about to renovate an old property and would like to take the=20
opportunity to get the infrastructure right for home automation.  The=20
received wisdom seems to be use 2CAT5e + 1CT100 to most rooms for=20
audio visual stuff, but I am a bit confused on the lighting and alarm=20
side.  What ever I put in now I want flexibility for the future.

A local electrical contracting company has urged me to star-wire the=20
lights so that a system like=20
http://www.domintell.com/en/index.html
.  This seems to be the same=20
requirement as C-bus where dimming is done by a din-rail device, but=20
with a different control wire system.  Problem is I cannot afford any=20
of the controls at the moment so would have to wire it with a mains=20
powered switch for now and then run a control cable down the conduit=20
at a later date.  While I would value a reliable system is this level=20
of dedicated wiring really necessary?  It seems to be very=20
restrictive for future development of the system.  How do RF devices=20
like Rako and Zwave compare?

I was very interested in the recent thread on motion detection.  I=20
want this feature for the hall-stairs and landing lights.  I was=20
amazed by Malcolm's set-up with so many devices controlled or=20
monitored (how did you do it?), but wondered if a simple approach=20
would work? Use a PIR from an outside light =96 comes with day-light=20
sensor and motion detection can be very sensitive =96 and no need for a=20
computer to be running all the time.  I know this may be heresy.=20=20
Obviously this would be the limit of its ability but for occupancy=20
could a normal alarm be used and a feed to a HA PC taken from the=20
control panel?  If an alarm could be used in this way would you wire=20
with 6-core alarm cable or cat5 which may give the option for other=20
devices in the future?

So far I've estimated I need 54 low voltage cables returning to=20
Node0, exclusing any speaker cable runs plus a bunch of mains cable=20
for any star-wired lighting circuits. And that isn't including wires=20
for window reed-switches!  While this is possible =96 am I making it=20
too complicated??

FWIW I have a budget of =A31-2K (to include cable and initial devices /=20
software) and while I administered a UNIX system 12 years ago now I=20
can only really say I'm competent at VBA for Excel and a little Perl=20
mainly plagiarised from CPAN.

Many thanks for your advice
JonS