Method for monitoring products in a refrigerator

1. Method for monitoring products in a refrigerator, which refrigerator ( 1 ) comprises at least one compartment ( 2 ) for holding products ( 3 ), a door ( 4 ) designed to close off said compartment ( 2 ), radio frequency transmission systems ( 5 ) serving to communicate with a plurality of transponders ( 6 ) that are assigned to said products ( 3 ) for the detection of the presence of the transponders ( 6 ) in the compartment ( 2 ), each transponder ( 6 ) being able to transmit a specific identification code, a control device ( 8 ) designed to memorize and compare the identification codes, sensors ( 10 ) connected to said control device ( 8 ), adapted to monitor said door ( 4 ) for detecting a time-based door-opening event and a time-based door-closing event, said method being characterized in that it includes:

detecting by means of said sensors ( 10 ) a time-based door opening event and a time-based door closing event for a differentiation, by means of said control device ( 8 ), between a closed-door state and an open-door state;

providing, by means of said control device ( 8 ), after detecting the time-based door opening event, a first time interval that immediately follows said time-based door opening event and is representative of a dynamic door opening phase, said first time interval being counted from a beginning of the time-based door opening event and having a predefined duration short enough to not allow a user to insert or remove any products ( 3 ) during said first time interval of the dynamic door opening phase;

detecting the presence of products ( 3 ) in the compartment ( 2 ) during that first time interval by the detection of the transponders ( 6 ) associated to said products ( 3 ) by means of said radio frequency transmission systems ( 5 ), and memorizing, by means of said control device ( 8 ), the identification codes of the detected transponders;

continuously detecting, by means of said radio frequency transmission system ( 5 ), during an entire open door state, the presence of transponders ( 6 ) in relation to the compartment ( 2 ), memorizing, by means of said control device ( 8 ), the time-based detection events of the transponders ( 6 ) and updating, by means of said control device ( 8 ), said time-based event as a function of a last detection of the transponders by the radio frequency transmission system ( 5 );

providing, by means of said control device ( 8 ), after detecting the time-base door closing event, a second time interval that immediately precedes said time-based door-closing event and is representative of a dynamic door closing phase, said second time interval being counted backward from a beginning of said time-based door-closing event and having a predefined duration short enough to not allow a user to insert or remove any products during the said second time interval of the dynamic door closing phase;

selecting, by means of said control device ( 8 ), the identification codes of the transponders ( 6 ) whose memorized time-based detection event during the open-door state falls within said second time interval of the dynamic door closing phase;

comparing, by means of said control device ( 8 ), the identification codes of the transponders ( 6 ) thus selected with those detected during said first time interval of the dynamic door opening phase;

assuming, by means of said control device ( 8 ), that the transponders ( 6 ) detected only during said second time interval have been inserted in the compartment ( 2 ) of the refrigerator ( 1 ) during the open-door state; and

assuming, by means of said control device ( 8 ), that the transponders ( 6 ) detected during said first time interval but were not detected during the second time interval have been removed from the compartment ( 2 ) of the refrigerator ( 1 ) during the open-door state.

2. Method as in claim 1 , comprising:

computing, by means of said control device ( 8 ), in response to the detection of the time-based door-opening event, the first time interval, said first time interval having a duration of about 0.5-1 second.

3. Method as in claim 1 , comprising:

memorizing, by means of said control device ( 8 ), the time-based event of the last detection of the transponders ( 6 ) during said open-door state.

4. Method as in claim 3 , comprising:

generating, by means of said control device ( 8 ), a selection list containing the identification codes of the transponders ( 6 ), whose last time-based detection event falls within the second time interval.

5. Method as in claim 4 , comprising:

assigning, by means of said control device ( 8 ), an IN/UNREADABLE reference status to the identification codes included in the list, and

assuming, by means of said control device ( 8 ), that the transponders ( 6 ) that were not detected during the closed-door state and during the dynamic door opening phase and whose identification codes have the IN/UNREADABLE status, have been inserted in the refrigerator during the open-door state.

6. Method as in claim 4 , comprising:

assigning, by means of said control device ( 8 ), an IN/UNREADABLE status to the identification codes contained in the list,

assuming, by means of said control device ( 8 ), that the transponders ( 6 ) detected during at least one of the closed-door states and the dynamic door opening phase and whose identification codes are IN/UNREADABLE, are transponders ( 6 ) that remain in the refrigerator ( 1 ).

7. Method as in claim 4 , comprising:

assigning, by means of said control device ( 8 ), the reference status IN/UNREADABLE to the identification codes that are not included in the list and were detected only during the intermediate phase.

8. Method as in claim 4 , comprising:

assigning, by means of said control device ( 8 ), an OUT reference status to the identification codes of the transponders ( 6 ) that are not included in the list and were detected during at least one of the closed-door states and the dynamic door opening phase, and

assuming, by means of said control device ( 8 ), that said transponders ( 6 ) whose identification codes have the OUT status have been removed from the refrigerator during the open-door state.

9. Method as in claim 1 , comprising:

backward counting, by means of said control device ( 8 ), in response to the detection of the time-based door closing event, the second time interval of the dynamic door closing phase starting from the time-based door-closing event, said second time interval elapsing, prior to the time-based door closing event, after a duration of about 0.5-1 second.

10. Method as in claim 1 , comprising:

identifying, by means of said control device ( 8 ), the transponders ( 6 ) that were detected during the closed-door state but were successively no longer detected during a full door opening/closing cycle, and

assuming, by means of said control device ( 8 ), that said transponders ( 6 ) are no longer present in the refrigerator.

11. Method as in claim 1 , comprising:

identifying, by means of said control device ( 8 ), the transponders ( 6 ) whose identification codes have an IN/READABLE reference status and which are no longer detected in a full door opening/closing cycle,

assigning, by means of said control device ( 8 ), an OUT reference status to the identification codes of the transponders ( 6 ) so identified, and

assuming, by means of said control device ( 8 ), that the transponders ( 6 ) whose identification codes have the OUT reference status are no longer in the refrigerator.

12. Method as in claim 1 , comprising:

identifying, by means of said control device ( 8 ), the transponders ( 6 ) that were detected during the open-door state but are successively no longer detected during a predefined number of full door opening/closing cycles, and

assuming, by means of said control device ( 8 ), that these transponders ( 6 ) are no longer in the refrigerator.

13. Method as in claim 1 , comprising:

identifying, by means of said control device ( 8 ), the transponders ( 6 ) whose identification codes have an IN/UNREADABLE reference status and which have no longer been detected during a predefined number of full door opening/closing cycles,

assigning, by means of said control device ( 8 ), an OUT reference status to the identification codes of the transponders ( 6 ) so identified, and

assuming, by means of said control device ( 8 ), that the transponders ( 6 ) whose identification codes have the OUT status are no longer in the refrigerator.

14. Method as in claim 1 , comprising:

assigning to the identification codes of the transponders ( 6 ) intended to be inserted in the refrigerator ( 1 ), an OUT reference status, using a programming station.

15. Method as in claim 1 , further comprising:

scanning, in a closed-door state preceding said time-based door opening event, said compartment ( 2 ) by means of radio frequency transmission systems ( 5 ) for the detection of the presence of transponders ( 6 ), and memorizing, by means of said control device ( 8 ), the identification codes of the detected transponders;

comparing, by means of said control device ( 8 ), the identification codes of the transponders ( 6 ) whose time-based detection event during the open-door state falls within said second time interval of the dynamic door closing phase, with those detected during the closed-door state; and

assuming that the transponders ( 6 ) detected during the closed-door state but were not detected during the second time interval have been removed from the compartment ( 2 ) of the refrigerator ( 1 ) during the open-door state.

16. Method as in claim 15 , comprising:

providing a full door opening/closing cycle including the following segments: the closed-door state, the open-door state, the dynamic door opening phase represented by the first time interval, and the dynamic door closing phase represented by a second time interval, said two dynamic phases taking place in the open-door state.

17. Method as in claim 16 , comprising:

assigning, by means of said control device ( 8 ), to each identification code a transponder ( 6 ), of a predetermined reference status as a function of the segment of the door opening/closing cycle in which the transponder ( 6 ) concerned was detected; and

memorizing, by means of said control device ( 8 ), that reference status.

18. Method as in claim 17 , comprising:

assigning, by means of said control device ( 8 ), an IN/READABLE status to the identification code of the transponders ( 6 ), detected during said closed-door state.

19. Method as in claim 18 , comprising:

providing, by means of said control device ( 8 ), an intermediate phase, within said open-door state, that develops between the dynamic door opening phase hand the dynamic door closing phase,

setting, by means of said control device ( 8 ), whereby within said intermediate phase no transition takes place in the reference status for the identification codes of the transponders ( 6 ) detected during the said intermediate phase, said identification codes maintaining the same reference status IN/UNREADABLE assigned in relation to the dynamic door opening phase.

20. Method as in claim 17 , comprising:

assigning by means of said control device ( 8 ), an IN/UNREADABLE reference status to the identification codes of the transponders ( 6 ), detected during the said first time interval of the dynamic door opening phase.