Humidity detection for hearing devices
Disclosed herein, among other things, are systems and methods for humidity detection for hearing device applications. A method includes calculating a capacitance between a terminal of a processor within a housing of an ear-wearable device and a designated ground plane within the housing. A temperature measurement is obtained from a sensor within the housing, and a humidity level is determined within the housing using the calculated capacitance and the obtained temperature measurement. The determined humidity level is compared to one or more predetermined humidity trigger levels, and a notification is sent to a wearer of the ear-wearable device conditioned on the comparison.
1. An ear-wearable device, comprising:
a housing;
a microphone within the housing; and
hearing electronics within the housing configured to be connected to the microphone, the hearing electronics including at least one processor and a memory including instructions that, when executed by the at least one processor, cause the at least one processor to perform operations to:
calculate a capacitance between a terminal of the at least one processor and a designated ground plane within the housing;
obtain a temperature measurement from a sensor within the housing;
determine a humidity level within the housing using the calculated capacitance and the obtained temperature measurement;
compare the determined humidity level to one or more predetermined humidity trigger levels; and
send a notification to a wearer of the ear-wearable device conditioned on the comparison.
2. The device of claim 1 , wherein, to calculate the capacitance, the memory further comprises instructions that cause the at least one processor to perform operations to:
set the terminal to an input mode;
actuate a first electrical switch to connect a pull-down resistor to the terminal;
monitor the terminal to determine that a first voltage at the terminal indicates that the terminal is set to a low level indicative of a logical zero;
upon determining that the terminal is set to the low level, actuate a second electrical switch to connect a pull-up resistor to the terminal;
initiate a timer upon actuating the second electrical switch;
monitor the terminal to determine that a second voltage at the terminal indicates that the terminal is set to a high level indicative of a logical one;
upon determining that the terminal is set to the high level, obtain a value from the timer; and
access a lookup table stored in the memory to determine the capacitance based on the obtained timer value.
3. The device of claim 1 , wherein to determine the humidity level, the memory further comprises instructions that cause the at least one processor to perform operations to:
access a lookup table stored in the memory to obtain the humidity level based on the calculated capacitance and the obtained temperature measurement.
4. The device of claim 3 , wherein the lookup table is device-specific with entries dependent on mechanical characteristics of the device.
5. The device of claim 1 , wherein the notification to the wearer is delivered via a mobile application on a smartphone in communication with the ear-wearable device.
6. The device of claim 5 , wherein the notification to the wearer includes a message with instructions for reducing humidity in the ear-wearable device.
7. The device of claim 1 , wherein the notification to the wearer is delivered via the ear-wearable device.
8. The device of claim 7 , wherein the notification to the wearer includes an audible notification.
9. The device of claim 1 , wherein the memory includes firmware for the device.
10. The device of claim 1 , wherein the ear-wearable device is a hearing aid.
11. A method, comprising:
calculating a capacitance between a terminal of a processor within a housing of an ear-wearable device and a designated ground plane within the housing;
obtaining a temperature measurement from a sensor within the housing;
determining a humidity level within the housing using the calculated capacitance and the obtained temperature measurement;
comparing the determined humidity level to one or more predetermined humidity trigger levels; and
sending a notification to a wearer of the ear-wearable device conditioned on the comparison.
12. The method of claim 11 , wherein calculating the capacitance includes:
setting the terminal to an input mode;
actuating a first electrical switch to connect a pull-down resistor to the terminal;
monitoring the terminal to determine that a first voltage at the terminal indicates that the terminal is set to a low level indicative of a logical zero;
upon determining that the terminal is set to the low level, actuating a second electrical switch to connect a pull-up resistor to the terminal;
initiating a timer upon actuating the second electrical switch;
monitoring the terminal to determine that a second voltage at the terminal indicates that the terminal is set to a high level indicative of a logical one;
upon determining that the terminal is set to the high level, obtaining a value from the timer; and
accessing a lookup table to determine the capacitance based on the obtained timer value.
13. The method of claim 11 , wherein determining the humidity level includes:
accessing a lookup table to obtain the humidity level based on the calculated capacitance and the obtained temperature measurement.
14. The method of claim 11 , wherein calculating the capacitance between the terminal of the processor and the designated ground plane includes calculating the capacitance between a general purpose input/output (GPIO) wire of the processor and the designated ground plane.
15. The method of claim 11 , wherein calculating the capacitance between the terminal of the processor and the designated ground plane includes calculating the capacitance between the terminal of a system on chip (SoC) processor and the designated ground plane.
16. The method of claim 11 , further comprising:
calculating the capacitance between multiple terminals of the processor and multiple designated ground planes to determine humidity levels at multiple locations within the housing.
17. The method of claim 11 , wherein obtaining the temperature measurement from the sensor within the housing includes obtaining the temperature measurement from a temperature sensor of an inertial measurement unit (IMU) within the housing.
18. The method of claim 11 , wherein sending the notification to the wearer of the ear-wearable device includes sending instructions to the wearer for reducing humidity within the ear-wearable device.
19. The method of claim 11 , wherein sending the notification to the wearer of the ear-wearable device includes sending an audible notification to the wearer using the ear-wearable device.
20. The method of claim 11 , wherein sending the notification to the wearer of the ear-wearable device includes sending the notification to the wearer of a hearing aid.