Detecting several different signals within a certain distance? Answered
I essentially need a device that emits a signal, while simultaneously tracking whether another device emitting the same signal enters a certain distance. If another device enters said distance then it will alert the wearer. I think this is possible, but haven't quite got the knowledge on whether it is possible.
I thought about using GPS to relay wearers position to a server, which can calculate whether another device is in the vicinity and to send a reply back to the wearer, but to send data would be a continuous cost, something I'm trying to eliminate.
Radio frequencies may be another avenue to go down, but again, not sure.
In my mind I would have say 10 devices attached to different people in a rural area, and each person would be able to tell if there was another person (and device) in say 100m.
Anyone got any ideas?