Clothes dryer wireless moisture data transfer systems and energy-efficient methods of operation

1. A method of operating a near field communication (NFC) tag, the NFC tag being secured to a rotatable drum of a clothes drying appliance, the method comprising:

determining whether the drum is currently rotating;

when it is determined that the drum is not currently rotating, disabling power consumption by one or more components of the NFC tag, the one or more components comprising a NFC tag controller; and

when it is determined that the drum is currently rotating, periodically switching the NFC tag between a normal mode and a low power mode.

2. The method of claim 1 , wherein determining whether the drum is currently rotating comprises:

determining whether a voltage has been induced across a first antenna of the NFC tag by a second antenna of an NFC reader.

3. The method of claim 2 , wherein determining whether a voltage has been induced across a first antenna of the NFC tag by a second antenna of an NFC reader comprises:

reading an external interrupt flag, wherein a value of the external interrupt flag is modified when the voltage is induced across the first antenna of the NFC tag by the second antenna of the NFC reader.

4. The method of claim 1 , wherein periodically switching the NFC tag between a normal mode and a low power mode comprises:

operating the NFC tag in the low power mode until a real time clock interruption occurs; and

when the real time clock interruption occurs, operating the NFC tag in the normal mode.

5. The method of claim 4 , wherein the real time clock interruption occurs periodically upon the expiration of a periodic amount of time, the real time clock counting the periodic amount of time.

6. The method of claim 4 , wherein operating the NFC tag in the low power mode comprises disabling power consumption by all components of the NFC tag except for a real time clock of the NFC tag.

7. The method of claim 4 , wherein operating the NFC tag in the normal mode comprises:

converting moisture data received from one or more moisture sensors positioned within the drum from analog data to digital data;

storing the digital data in a memory of the NFC tag.

8. The method of claim 7 , wherein operating the NFC tag in the normal mode further comprises:

after storing the digital data in the memory of the NFC tag, determining whether the drum is still rotating;

when it is determined that the drum is still rotating, returning the NFC tag to the low power mode; and

when it is determined that the drum is not still rotating, disabling power consumption by the one or more components of the NFC tag controller.

9. The method of claim 8 , wherein operating the NFC tag in the normal mode further comprises:

prior to determining whether the drum is still rotating, clearing an external interrupt flag, wherein a value of the external interrupt flag is modified when a voltage is induced across a first antenna of the NFC tag by a second antenna of an NFC reader;

wherein determining whether the drum is still rotating comprises reading the external interrupt flag, whereby it is determined whether the drum has rotated such that the NFC tag was placed adjacent to the NFC reader since the clearing of the external interrupt flag.

10. The method of claim 7 , wherein the memory comprises an electrically erasable programmable read-only memory.

11. The method of claim 1 , wherein the NFC tag is powered by a battery, and wherein the ultra-low power mode and the low power mode conserve stored energy of the battery.

12. A clothes dryer, comprising:

a cabinet;

a drum rotatably mounted within the cabinet, the drum defining a space for the receipt of clothes for drying;

one or more sensors positioned within the drum, wherein the one or more sensors respectively output one or more output signals indicative of an amount of moisture contained within the clothes;

a near field communication (NFC) tag positioned on an exterior surface of the drum and wired to receive the output signals from the plurality of sensors, wherein the NFC tag uses near field communication to provide sensor data to an NFC reader positioned exterior to the drum and in operative communication with a controller of the clothes dryer, such that the operation of the clothes dryer can be controlled based on the amount of moisture contained within the clothes; and

a power supply electrically connected to the NFC tag;

wherein the one or more sensors, the NFC tag, and the power supply are secured with respect to the drum so as rotate concurrently with the drum;

wherein the NFC reader is stationary and positioned adjacent to a rotational path of the NFC tag;

wherein when the drum is not rotating, one or more components of the NFC tag are disabled from consuming power, the one or more components comprising a NFC tag controller; and

wherein when the drum is rotating, the NFC tag periodically transitions between a lower power state and a normal state.

13. The clothes dryer of claim 12 , wherein:

when the NFC tag operates in the low power state, all components of the NFC tag except for a real time clock are disabled from consuming power.

14. The clothes dryer of claim 12 , wherein:

when the NFC tag operates in the normal state, the NFC tag:

receives moisture data from one or more moisture sensors; and

writes the received moisture data to a memory of the NFC tag.

15. The clothes dryer of claim 12 , wherein the NFC determines whether the drum is rotating based at least in part on whether a voltage has been induced across a first antenna of the NFC tag by a second antenna of the NFC reader.

16. A method for operating a wireless communication tag of a moisture sensing system of a clothes drying appliance, the method comprising:

determining whether a drum of the clothes drying appliance is rotating, wherein the wireless communication tag rotates concurrently with the drum;

when it is determined that the drum is not rotating, disabling power consumption by one or more components of the NFC tag until it is determined that the drum is rotating, the one or more components comprising a NFC tag controller;

when it is determined that the drum is rotating, periodically transitioning the wireless communication tag between a normal mode and a low power mode;

wherein operating the wireless communication tag in the normal mode comprises:

writing received moisture data to memory; and

after writing the received moisture data to memory, placing the wireless communication tag into the low power mode; and

wherein operating the wireless communication tag in the low power mode comprises:

disabling one or more components of the wireless communication tag from consuming power;

waiting for a real time clock interruption; and

when the real time clock interruption is received, placing the wireless communication tag into either the normal mode or the ultra-low power based at least in part on whether the drum is still rotating.

17. The method of claim 16 , wherein determining whether the drum of the clothes drying appliance is rotating comprises determining whether a voltage has been induced across a first antenna of the wireless communication tag by a second antenna of a wireless communication reader, wherein the wireless communication reader is stationary and positioned adjacent to a rotational path of the wireless communication tag.

18. The method of claim 17 , wherein:

operating the wireless communication tag in normal mode comprises clearing an external interrupt flag; and

determining whether the voltage has been induced across the first antenna of the wireless communication tag by the second antenna of the wireless communication reader comprises reading the external interrupt flag, wherein a value of the external interrupt flag is modified when the voltage is induced across the first antenna of the wireless communication tag by the second antenna of the wireless communication reader.