I want my router to report (preferably by making a php POST containing MAC address) every time a device connects/disconnects. I currently have a Netgear router (which is able to run dd-wrt), but I'm willing to buy a different router if it's necessary.
(Context: I have automated my home to the extent that when my wife and I both have left the house (i.e. our phones disconnects from our wifi), all lights will switch off. I'm using the Android app Tasker to achieve this per now - by sending HTTP POST requests from the phones to my server. However, the switch from wifi to 3g sometimes make the POST fail, and my server doesn't catch that we've left the house. My guess is that if I could make the POST from the router instead, I would get a more reliable solution.)