Proximity Arming of Alarm.

Hello.

What i want to do is have a car alarm, that is armed by my phone. That is, when i walk away with my phone, the system is automatically armed, and when i come back, it is disarmed.

My phone has bluetooth, so my thought is to use a bluetooth module and run software to detect whether or not the bluetooth module is connected or disconnected. Or, better yet, view the RSSI values of the bluetooth connection, so that i can adjust the arming/disarming range.

I was considering this module, as Adafruit has a iphone app:

However, i was unsure if the module will automatically connect to my phone or if the app has to be running in order for the connection to be made?

Is anyone familiar with this app? If this won't work i had also considered using RFID keychains, but i've heard their range is only a few feet, and it might not work in my car depending on the placement of the modules/keychain.

Thanks!

Usually a paired bluetooth device doesn't need the app running. The bluetooth connections are managed outside the apps, although most apps which require a bluetooth connection will have a shortcut to the appropriate settings menu.

Yes, RFID is usually much shorter range. With a large antenna, you can push out the range. Think about the antennas you see on the exit of stores with RFID security tags on the merchandise.