I am trying to build a system where, when and only when someone is within close proximity, about 20 cm or so, two arduino like devices can communicate wirelessly.
I want to be able to communicate data from the device back to the human, and data from the human to the device, probably with some kind of antenna mounted in the back of a glove.
I was looking into nfc, but it appears that nfc is one way.
What are your suggestions?
For clarification, I would like to add that there would be many devices that the user may or may not choose to use.