I just got myself some new fire alarms that can be connected together with a 2-wire cable, so that if one triggers they will all sound the siren. A quick test later I can tell they do this by applying 9v power from the battery directly to the cable. Simple enough to detect with a voltage divider and analog input on the arduino.
So, what if I'm not at home and there is a fire? I'd like to be alerted if possible. My thought is to use something like an arduino or similar and have it notify me by SMS, or maybe just e-mail (works almost as well with a smartphone these days). SMS will be quicker since e-mail requires my phone to check for e-mail first, but it's a cost vs. speed issue really. There are planty of automation apps for android out there that could sound the alarm when receiving a certain message or from a certain number. The arduino would be powered by a wall wart, and maybe I'll add a backup battery as well.
How would you go about to solve this? I don't mean in detail, but would you use arduino with SMS shield? Do you see any major problems with my idea? Got ideas of how to improve the sollution? Does it all sound stupid? Is there a cheaper sollution? Let me know. :)