I am looking for a way to transmit data when two phones are close by. This needs to be cross platform so I cannot use NFC or iBeacon. I plan on using allJoyn to send information. I would only like to send data to others that are within a few feet of me.
Is there any way that I could get an accurate reading of distance on other phones? Or can I get an accurate distance on a master device that could be placed in the room?