I found a nice little feature in hostapd which can trigger stuff when devices connects and disconnects to it, which means it's quite simple to control stuff in Homeautomation using the presence of wifi units. I wrote a little howto, I hope it's meaningful to someone
http://wiki.excito.org/wiki/index.php/C ... i_presence
Please note though that until we get hostapd 1.0 on our Bubbas (the version on B3 is currently 0.7.2) the lights won't go off automatically when you leave the house, since hostapd doesn't send a signal when a device just disappears, only when it implicitly disconnects. I'm hoping for a hostapd upgrade though (Excito: Please with sugar on top?
), which will make this perfect!/Daniel