As I’ve mentioned before, I use an iBeacon on my wheelchair so that I can limit the detection area just to the length of the wheelchair ramp and I avoid the “bus stop problem” where the bus stops on my block but the driver takes a few minutes to get me unloaded. Works well for me, and is totally hands-free.
There’s discussion of multiple options, including that one, in the presence FAQ. Note, however, that all of these work only with the classic app, as the new app does not allow you to automate unlocking the door.
