System and method to determine sterilization of a device
View Patent ↗A system and method for verifying the occurrence of an environmental condition is disclosed. Rather than store information concerning the occurrence and/or success of the sterilization process, the present invention modifies the wireless transmission characteristics of the device. In some embodiments, the bandwidth of the wireless transceiver is altered as a result of undergoing sterilization. In other embodiments, the resonance frequency of the circuit is affected. In other embodiments, one or more of these parameters are affected based on other environmental conditions, such as shock or vibration.
1. A wireless identification device, comprising: an RFID integrated circuit, and an external circuit, adapted to tune the frequency of wireless transmissions, said external circuit comprising an inductor, a capacitor, a resistor, a first variable component, wherein said first variable component has an open state and a closed state, wherein said state of said first variable component is determined based upon exposure to a first environmental condition, and a second variable component, wherein said second variable component has an open state and a closed state, wherein said state of said second variable component is determined based upon exposure to a second environmental condition, said second environmental condition is of a kind different than said first environmental condition, and wherein said inductor, said capacitor, said resistor, said first variable component and said second variable component determine a resonant frequency and bandwidth of said device, wherein said first variable component affects only said bandwidth and said second variable component only affects said bandwidth.
2. The wireless identification device of claim 1 , wherein said first variable component is in series with said resistor and said external circuit comprises a second resistor in series with said second variable component, wherein said second resistor and said second variable component are in parallel with said first variable component and said resistor.
3. The wireless identification device of claim 1 , wherein said first environmental condition and said second environmental condition are selected from the group consisting of shock, elevated temperature, depressed temperature and radiation.
4. A method of verification that an item has been subjected to at least one of a plurality of environmental conditions, comprising: affixing an RFID device on said item, said RFID device comprising an RFID integrated circuit, and an external circuit, adapted to tune the frequency of wireless transmissions, said external circuit comprising an inductor, a capacitor, a resistor, a first variable component, wherein said first variable component has an open state and a closed state, wherein said state of said first variable component is determined based upon exposure to a first of said plurality of environmental conditions and a second variable component, wherein said second variable component has an open state and a closed state, wherein said state of said second variable component is determined based upon exposure to a second of said plurality of environmental conditions, said second environmental condition is of a kind different than said first environmental condition, and wherein said inductor, said capacitor, said resistor, said first variable component and said second variable component determine a resonant frequency and bandwidth of said device, wherein said first variable component affects only said bandwidth and said second variable component only affects said bandwidth; interrogating said RFID device with an external RFID reader; comparing said bandwidth to a predetermined value; and verifying said item has been subjected to at least one of said plurality of said environmental conditions based on the result of said comparison.
5. The method of claim 4 , wherein said first and said second of said plurality of environmental conditions are selected from the group consisting of shock, elevated temperature, depressed temperature and radiation.
6. The method of claim 4 , wherein said first variable component is in series with said resistor and said external circuit comprises a second resistor in series with said second variable component, wherein said second resistor and said second variable component are in parallel with said first variable component and said resistor.
7. The wireless identification device of claim 1 , wherein said first variable component is in series with said resistor, said second variable component is in series with a second resistor, and said external circuit comprises a third resistor, in parallel with said first variable component and said resistor and in parallel with said second variable component and said second resistor.
8. The method of claim 4 , wherein said first variable component is in series with said resistor, said second variable component is in series with a second resistor, and said external circuit comprises a third resistor, in parallel with said first variable component and said resistor and in parallel with said second variable component and said second resistor.
9. The method of claim 4 , further comprising determining which of said first and second environmental conditions said device has been exposed to.