Burgler alarm on open door

[Verkenner]

Want to see when someone is walking into my house. So a burglary-alarm.
On the backside of my house is a slidingdoor wich can be open between 0 and 100 centimeter (for fresh air).
The door is unlocked. We have no animals (but me).
I prefer a wireless sign to HomeSeer when a prowler comes into my living.

A door-mat with presure-sensor is undesirable, because of fake alarms.

A solution can be a IR-wireless system like a Passive Infrared Sensor (PIR).
I like the HSM100 but up til now I have none Z-wave-receivers.
Or something like X10 over RF (I have a SC-2800).

Has someone suggestions to secure this open door with an (audible) alarm ??
I know that I can lock the door

[Henk]

You can use a PIR and narrow the detection area or use a "licht sluis" a beam of IR light emitted by the sender and being reflected by the reflector and received back .. in case this beam will be interrupted a relay will be switched - you can contact a wireless doorcontact to this device... Conrad has a number of licht sluizen ....

Henk

[Esteban]

I'd go with light beam sensors (lichtsluizen) in this case. They allow for a nicely localized detection and are easier to hide from the view of the person coming in.