I am wanting to have the doors unlock when I get close. I figured this could be accomplished by a zwave lock with a ST hub and the ST proximity sensor key fob. My only question is what will be sensing for the location of the key fob? If it’s the ST hub, how will it differentiate from being close to the front door or back?
Yep that’s the problem with either the phone or the Zigbee fob, it’s a 360° circle and so it may cover more space than you want.
I use a wheelchair and I ran into what I called the “bus stop” problem. I have a door with an autolock. But it can take the bus driver several minutes to unload me from the bus. So the zigbee presence sensor was detecting me while I was still on the bus, unlocking my door, and locking it again before I got there.
About the only way around this is to add a second device that will more precisely locate you physically. There are a lot of options for this. You can use a contact sensor, A motion sensor, an I Beacon, even a pressure mat under the welcome mat at the door.
So now one device physically pinpoints you, but doesn’t know who you are, and the other device (either phone or Zigbee fob) does recognize that it’s you.
It’s not absolutely perfect microlocation, but it worked a lot better for my use case then just using one device.