I have many slaves and many masters, I want them to communicate wirelessly and autonomously.
If one slave S1 sends a message to the nearby master M1, then M1 should respond only to S1.
What should be used for communication? Bluetooth? RFID?
Distance: 1-100m
What product I need to buy?
I’m sorry I can’t give you an answer but the two that you have now, Bluetooth and RFID, won’t have the distance of 100 m. RFID is likely to be no more than 1 to 2 m at the absolute best (usually less than 1 m) and Bluetooth will likely top out at 25 to 30 m.
This is outside of my knowledge area but some thoughts. Will these be line of sight where you could use IR (don’t forget ambient light will reduce range)? 802.11?
Or
http://www.airspayce.com/mikem/arduino/RadioHead/
http://www.anarduino.com/details.jsp?pid=145
Bluetooth range too short,and it isn’t intended for telemetry.
IR not 100m, not outdoors.