Surgical implement detector

A detector system for detecting at least two RFID tags each having an RF antenna and being configured to transmit therefrom a signal containing a modulated carrier frequency impressed with an identification code, the detector system comprising:

• a presence detector having an interrogating antenna configured to transmit a carrier frequency;
• and
• wherein:
• the RF and interrogating antennae are coupleable to one another within a presence range;
• each one of the RFID tags being configured to transmit signals in response to the carrier frequency received from the interrogating antenna;
• the interrogating antenna being configured to receive signals from at least one of the following:
• signals transmitted by at least one of the RFID tags, signals transmitted by a combination of environmental noise and at least one of the RFID tags;
• the presence detector further including:
• a signal reader configured to receive the modulated carrier frequencies from the RFID tags during a predetermined response time period for comparison to a reference level for determining the presence of RFID tags within the presence range.

A detector system for detecting a plurality of items each having at least one RFID tag secured thereto, each one of the RFID tags being operative to transmit an identification code, the detector system comprising:

• a presence detector operative to detect the presence of at least one of the RFID tags within a presence range between the presence detector and the RFID tags;
• a message detector operative to detect the identification code of at least one of the RFID tags within a message range between the presence detector and the RFID tags;
• and
• an indicator device connected to the presence and message detectors;
• wherein the presence and message detectors are operative to cause the indicator device to indicate the existence of at least one of the following three states:
• non-presence of RFID tags, presence of at least one RFID tag, identification code of at least one of the RFID tags.

A method for detecting a plurality of items each having an RFID tag secured thereto, the method comprising the steps of:

• a. establishing a reference level during a quiet period;
• b. transmitting a carrier frequency from a presence detector;
• c. receiving the carrier frequency at the RFID tags located within a presence range of the presence detector;
• d. impressing an identification code of each of the RFID tags onto a plurality of the carrier frequencies by modulation thereof;
• e. transmitting the modulated carrier frequencies from the RFID tags to the presence detector;
• f. receiving at the presence detector during a predetermined response time period a composite signal comprised of at least one of the following:
• signals transmitted by at least one of the RFID tags, signals transmitted by a combination of environmental noise and at least one of the RFID tags;
• g. comparing the composite signal to the reference level;
• and
• h. generating a comparator signal when the composite signal is distinguished from the reference level.