[ILUG] OT - Good burglar alarms with a serial port

[Philip Trickett (List)]

On Wed, 2008-12-03 at 18:04 +0000, Michael Watterson wrote:
> Philip Trickett (List) wrote:
> > Hi,
> >
> > I just thought I would ask here, as I seem to remember a blog entry of
> > someone on ILUG about an automated sms from his linux box when his
> > burglar alarm was activated.
> >
> > Does anyone have an alarm with an RS232 port, and if so, is it any good?
> >
> > I was thinking of linking it in with either Mythtv or with Zoneminder,
> > so when it is activated, I could get an email with a picture attachment,
> > or log in from my mobile to check cameras in the house.
> >
> > Thanks,
> >
> > Phil
> >
> >   
> Wire the alarm output relay contact to a serial port Handshake in line 
> (choice of two main ones). Do what ever you like when it changes. If TXD 
> or one of the two output handshake lines is connected via 10k Ohm 
> resistor, the handshake line will be by default +5V to +12V. The alarm 
> contact closing puts it to zero.
> 
> ANY alarm can be wired up this way.
> 
> Polling the state of the handshake every 20 seconds is more than 
> adequate and little overhead.
> 

Good idea, and one I might pursue.

I was looking more from the point of trying to get more information from
the alarm, such as what zone or sensor triggered the alarm, whether
there are any faults etc.

That way, it could be used to determine if say a garage door had been
triggered, rather than front door / back door etc.

Phil