WIRELESS CULINARY PROBE CALIBRATION METHOD AND SYSTEM

1 . An apparatus for calibrated control of a cooking oven comprising:

an oven heat source ( 120 );

a thermostat ( 115 ) providing temperature control signals to said heat source ( 120 );

a wireless temperature probe ( 110 ), said probe comprising a sensor body, at least one surface acoustic wave (SAW) temperature sensor ( 305 ), and at least one sensor antenna ( 310 );

a separate probe transceiver calibration unit ( 105 , 325 ) receiving temperature information from said temperature sensor of said probe, said probe transceiver calibration unit comprising an antenna ( 330 ) electrically connected to said probe transceiver calibration unit ( 105 , 325 );

a calibration material ( 315 ) in a calibration material container ( 320 );

said probe transceiver calibration unit ( 105 , 325 ) receiving thermal properties of said calibration material and configured to calculate a calibration factor to apply to a decoded uncalibrated temperature reading from said probe, producing a calibrated temperature from said probe;

whereby said oven thermostat ( 115 ) receives calibrated temperature reading control input from said probe transceiver calibration unit ( 105 , 325 ).

2 . The apparatus of claim 1 comprising a pre-calibration sequence ( 1110 - 1140 ).

3 . The apparatus of claim 1 wherein said probe is calibrated without a reference temperature sensor.

4 . The apparatus of claim 1 wherein calibration is accomplished at a single temperature point ( 570 , 615 , 715 ), and calibration calculations are performed in said probe calibration unit ( 105 , 325 ).

5 . The apparatus of claim 1 wherein said probe ( 110 ) comprises a response time of at least about one second, an accuracy of about 0.5 degrees C., a precision of about at least 0.5 degrees C., a linearity of about 1% over a temperature range of about 0 to about 250 degrees C., and a drift of less than about 0.1 degree C. per year.

6 . The apparatus of claim 1 wherein quantity of said calibration material is minimized.

7 . The apparatus of claim 1 comprising ending a pre-calibration sequence when SAW sensor measured temperature varies by no more than approximately 0.5 degrees Celsius.

8 . A method for calibrating a culinary probe comprising the steps of:

providing a calibration material ( 910 );

placing one sensor in said calibration material in an oven ( 915 );

beginning a heating operation by controlling a heat source by a thermostat ( 920 );

detecting a temperature plateau of said calibration material in a probe calibration unit ( 925 );

adjusting a reading of said sensor to correspond to a calibration temperature ( 930 );

saving settings ( 935 ); and

controlling said heat source by said thermostat receiving calibrated temperature control input from said probe calibration unit ( 1195 ).

9 . The method of claim 8 comprising:

receiving information about heating power, thermal properties of said calibration material; probe unique identifier; and calibration material unique identifier at said probe calibration unit ( 1015 ), and recording, at said probe calibration unit, a time at which a temperature of said calibration material does not increase ( 1185 ).

10 . The method of claim 8 comprising:

storing, in said probe calibration unit, said information about a correlation between said time at which the calibration material temperature does not increase and thermal properties of said calibration material; and

said probe unique identifier ( 1185 ).

11 . The method of claim 8 comprising:

calculating, in said probe calibration unit, a calibration factor to apply to said decoded uncalibrated temperature reading from said probe, producing a calibrated temperature from said probe ( 1185 ).

12 . The method of claim 8 comprising a pre-calibration sequence comprising:

activating a SAW temperature sensor with an RF signal ( 1110 );

decoding uncalibrated temperature and probe ID from a SAW response signal ( 1115 );

saving said uncalibrated temperature associated with said probe and calibration material identifications and time ( 1120 );

waiting for a measurement interval ( 1125 );

repeating activating decoding and saving cycle ( 1130 );

comparing consecutive uncalibrated temperatures from said SAW ( 1135 );

checking to determine if temperature is unchanged, stable at ambient temperature ( 1140 );

if not unchanged, wait for said measurement interval, if unchanged, temperature is stable at ambient temperature, ending said pre-calibration sequence.

13 . The method of claim 8 comprising:

collecting approximately 300 data points for calibration calculation, and collecting data from said probe at about one second intervals.

14 . The method of claim 8 comprising:

immersing said probe in water calibration material, and removing said calibration material from said oven after completion of calibration and cooking initiation.

15 . A system for calibrating a culinary probe comprising:

activating a SAW temperature sensor with an RF signal ( 1110 );

decoding uncalibrated temperature signal and probe ID from a SAW response signal ( 1115 );

saving said uncalibrated temperature associated with said probe and calibration material identifications and time ( 1120 );

waiting for a measurement interval ( 1125 );

repeating said activating, decoding, and saving cycle steps ( 1130 );

comparing consecutive uncalibrated temperatures from said SAW sensor ( 1135 );

checking to determine if temperature is unchanged, stable at ambient temperature ( 1140 );

beginning energizing a heat source controlled by a thermostat ( 1150 );

performing a sequence comprising activating said SAW sensor, decoding a SAW sensor response, saving said SAW response, probe and calibration material identifications, and time ( 1155 );

waiting for said measurement interval ( 1160 );

comparing consecutive uncalibrated temperature sensor responses from said SAW sensor ( 1165 );

checking to determine if temperature reading has increased ( 1170 );

if temperature has increased, repeating said activating, decoding, saving cycle steps ( 1155 );

if temperature has not increased, confirming that said heat source is on ( 1175 );

collecting a predetermined quantity of uncalibrated temperature reading repetitions at a stable temperature ( 1180 );

calculating and saving a calibration factor for said SAW probe and said material by said respective identifications ( 1185 );

de-energizing said heat source ( 1190 );

ending calibration steps; and

controlling said heat source by said thermostat receiving calibrated temperature control input from a probe transceiver calibration unit ( 1195 ).

16 . The system of claim 15 , comprising collecting a predetermined quantity of uncalibrated temperature reading repetitions at said stable temperature only if said heat source is confirmed to be on ( 1180 ).

17 . The system of claim 15 , comprising setting a setpoint temperature of said thermostat to at least a change-of-state temperature of said calibration material ( 1015 ).

18 . The system of claim 15 , comprising energizing said heat source ( 1150 ) if said heat source is determined to not be on at said step of confirming that said heat source is on ( 1175 ).

19 . The system of claim 15 , wherein power supplied to said heat source during heating is varied proportionate to a thermal inertia of said calibration material, whereby a given time for calibration is maintained.

20 . The system of claim 15 , comprising:

requesting calibration to initiate said calibration at said probe transceiver calibration unit ( 1005 );

selecting said calibration material ( 1010 );

programming a controller in said probe transceiver calibration unit with calibration material physical properties values including change-of-state temperature ( 1015 );

identifying said probe from said probe ID from said RF signal ( 1020 );

confirming SAW temperature sensor operation with RF signal ( 1030 );

transferring control of said heat source to said probe transceiver calibration unit ( 1045 ) from said thermostat.