Arduino bicycle security "system"? Or something similar?
An idea I came up with is that, since I only leave my bike unlocked while going into a store, and I only go in with my friend(who also uses his bike), I would put an arduino board under each of our bikes. There would also be a third "receiver" board that one of us would put in our pockets. When the two bike boards are X feet away, the reciever as well as the boards would beep, flash, whatever.
So, my question is, put simply, is this possible? Exactly as outlined?
If not, how could I make it work and be similar, or at least as simple.
If it is, could you point me in the basic direction of what I would need to do with the Arduino, or w/e you think would be best.