Using mobile phone as switch

Hello!
Has anyone done something similar like connecting mobile phone to arduino board and used it as a remote switch? I mean if I call that phone, the arduino turns something on and when i call second time, it turns that thing off.

Well a cheap method might be to activate on the phones' ringing sound with a microphone/op-amp/rectifier circuit, or possibly strap an accelerometer to the phone and have the Arduino activate on the phone's vibrate mode.

However wrong numbers calling in might be a problem? ;D

PS: I hope you don't have any evil intentions for this application?

Lefty

I read about a neat trick somewhere - assign a picture to your number in the phone’s address book so that when you call the phone the picture comes up on screen (assuming the phone has this capability). Make the picture a pattern of bright and dark spots (like a 2D barcode), tape two or more light sensors to the screen and you should be able to tell if it’s the correct number calling as well as just the fact that the phone is ringing.

Andrew

retrolefty, no evil intentions - just trying to make some home remote/automation stuff. Bad ideas should stay in movies.
I found out that i can make "one-beep" ringtone.... so no pulsating tones that could make the switch to turn on-off continuously when i call too long. Also i was thinking about just using microphone + resistors. So when that mobile receives a call, makes beep and Arduino with mic will turn on digital output.

Andrew, yeah that's a bit more advanced, also i only have some monochrome Nokias, so no hi-tech techniques.