iPhones have this habit of running out of battery. That could be inconvenient. The battery in the key fob probably lasts on the order of months because that's its only purpose in life.

That's one way of seeing it... Usually when I am at work or work with my Mac most likely my phone is either with some decent battery % or being charged. So if I leave for a few min, my phone usually always goes with me thus will work fine without another device.

I just scan around and there is another app in the Mac AppStore: https://itunes.apple.com/us/app/keycard/id578513438?mt=12

And some tutorial: http://mac.tutsplus.com/tutorials/security/use-your-phone-to...

which reference another open source project -which seems left in the water for the past few years.

Anyway the concept overall is good but I think I am not the target market: not really interested to add one more BT devices that I need to carry.

Good luck to the team