This will involve an Arduino which will give the right commands to the RFID reader. When the setup finds a tag, it will do some action, probably make a sound, blink a led, or ... both!
-three tennis rackets (already taken care of)
-three RFID readers (also already taken care of)
-three Arduinos (depends still, but we better have them ;-))
-three battery holders (already taken care of)
-everything for the icing on the cake once the setup works as expected, think: light, noise etcetera, shouldn't be too hard ;-)
flash the RFID-reader so it'll boot in a 'seek tag' mode
hook up an arduino which will feed the 'seek tag' command through a serial connection.
write up including youtube-videos overhere: