Integrating existing PIRs into Homeseer

[robstokes]

Our house has an alarm system (a Scantronix 9750) which has a few wired PIRs around the house. These feed into the alarm system box under the stairs and, from what I can tell, run off 12v.

I was considering trying to integrate them into my homeseer system using some DS10a's connected to relay switches...

I'm imagining that the PIRs have a couple of wires and, when active, complete a circuit and send 12v back to the box... so if I attach a 12v relay, and then a DS10a it should activate when the PIR is active.

As you can probably tell, i'm no electrician! But is my theory sound? Anyone know how wired PIR's work and if my assumptions are correct?

Thanks in advance!

[Microchip]

Looking at the installation/programming manual you should be able to connect a low power relay from the contact input to either the +12V or the 0V depending which the common for the contacts is. See page 23/71 of the manual for more information.

To use the tamper switch detection you would require a relay for that also.

There is another way of connecting the relay but that depends on the resistance of the input circuit and the relay operating current/volts.
Obviously the relay contact would drive the DS10.

The DS12 could be used, it has 2 inputs built in as well as its own tamper switch.

Link to manual if you do not have one:-

http://www.homeguardsecurity.co.uk/p...50_install.pdf

[mrhappy]

I do and have done this for a number of years, what I found is that PIR's are NC contacts and only go open for a second or two before closing again so you have to be quick. When I ran the K8055 I could actually wire in parallel to the alarm panel zones and read both the inputs into HS and use the devices in my alarm. I do think that because the K8055 has isolated inputs I was able to get away with it, I since switched to PIC based stuff and still have the PIR's wired to inputs with a 10K resistor and they still report the status OK and I use them for motion lighting. You do have to obviously wire it to 12V to start with.

If all of the wires go back to your alarm box I would be tempted to start wiring devices in here, that way if you need to return to your old config it is easier to do so.