I was thinking of developing a new project for home, but I need a little guidance.... I'm trying to make a home security system that will be activated when a "smart key" is not in range of an arduino let's say. (something like smart-car-keys). Is it possible? What kind of arduino shield or "smart key" would I need?
Yes, I've misspelled that phrase, I want the alarm to be active when the key is not in range. I was thinking I can do this system with a RFID setup, but that means that the key (key-chain) must be in a specific place (on the RFID reader) for the alarm to be deactivated, and not be there for the alarm to be active.
That would be a simple solution, but I would love it if I could somehow make a system in which the key needs to be "in range" (4-5 meters) of the microcontroller or receiver for the alarm to be deactivated.
If I understand it correctly you want an alarm system that deactivates automatically when you are near or inside the house without specifcally switching it on or off by holding a RFID tag near a reader.
I get the impression that the new Bluetooth Low Energy system may be able to do what you say. You may find this Thread interesting.
Hmm, very interesting thread Robin2, but, I was thinking more at creating a project with a Bluetooth module for arduino (HC-05), and buying a bluetooth key and pairing them somehow.
I've found a tutorial for pairing 1 bluetooth module, to a smartphone, but that isn't quite what I need.
I wounder, can you pair a bluetooth module to another bluetooth module, and then transform the second module into something that someone can wear on their key-chain?
You will need to satisfy yourself that your system cannot fail by losing a connection (perhaps due to inteference) while you are in the house and switching the alarm on when you don't want it on.
I suspect you would need BLE if you want the low power consumption that a key-fob battery system would demand.