Different devices have different ranges and different technologies handle arranged differently. There are many options to get a smaller detection area.
If you are depending on The GPS technology used by phones, then it depends on where the cell towers are, and the range can actually vary a lot just depending on the direction you’re driving from.
Many people use a phone with their own at home Wi-Fi. This is what the onhub does with its IFTTT recipes. Other people have done something similar with smart things and their own Wi-Fi.
I use Ibeacons quite a bit because their detection range can be varied from about 2 inches up to about 15 meters. That works well for my use cases but might not work for someone who wanted their garage door to start opening half a block away.
You can also use the two device sequential detection method to specify range more precisely:
So if the only issue you’re having with your presence is that the area covered is too large, that’s fairly easy to fix now. It doesn’t address the other issues discussed with regard to micro location, though, like room definition, having to carry a device with you, and knowing who is who.