SIP Intercom

Why settle for a doorbell when you could make a SIP-enabled intercom?

Revision for finals is boring me, so I thought I'd take a break and my mind started wondering... wouldn't it be cool to give door-to-door salesmen the runaround, analogous to that Asterisk script that sends known cold callers into menu hell. Of course this would be possible if your door entry system incorporated an intercom that was a SIP device.

By butchering a cheap £3 Argos phone which you wouldn't miss if it got vandalised/rained on and connecting it to an indoor ATA, the intercom would then have its own identity in the Asterisk PBX, and visitors could press some big green button which dialled '9' or something in the intercoms context. We could then ask visitors questions which they can answer using the touch-tone keypad, e.g. specifying who they want, if they're salesman etc. One could even change the extensions.conf on Halloween.

If you're not in (ie your RFID rabbit is not on the house mir:ror reader), the intercom could take a message which could be saved on the server, or even better, it could call your mobile phone and patch the extensions together if you really wanted. Obviously you'd combine this with my Asterical script so you don't get calls in the middle of something important.

If you had lots of time, and either owned your house or had an extremely nice landlord, you could make Asterisk call a script that controlled an arduino, which could physically open the door. This would almost certainly invalidate your insurance policies, but it would make it possible to let in callers from the comfort of your own chair, and even remotely by dialling a PIN number on the phone.

Of course this is all crazy and I don't really plan on doing it, but my blog needed a new post and this was all I could come up with.

Posted 1st May 2009 in Computer, with 1 comment