We should have such a system, but I do not know what hardware to buy.
Which type RFID tag and RFID reader would be good for us ?
Do you think this would work? ( I can write the software )
UHF Reader (~5m): http://www.ebay.com/bhp/uhf-rfid-reader
UHF Tag: http://www.ebay.com/bhp/uhf-rfid-tag