the small lcd would be awesome i use a flip down hud eyepeice for night vision i dont hook it to arduino(dont know how). rfid tags that work acouple of inches would be great
reader in your glove/wrist of shouldermounted for rifles wuth a shoulder rest.
btw if anyone knows how to get arduino to display on (spygear hmd) or similat let me know.
i dont know about bluetooth it would have problems with range right?(being too sensitive)
like when a sidearm is holsterd accidently triggering.
althoug if you need 2 way comm like night vision/ammo
use a hibrid blutooth to connect all devices available, and rfid to designate the active wepon