On-head detection with touch sensing and eye sensing

1. A computer-implemented method comprising:

while a wearable device is operating in a first state and a first sensor is operating in an active mode:

initially operating an inward-facing second sensor in an idle mode; and

receiving an indication of a touch input at the first sensor;

in response to receiving the indication of the touch input: (a) triggering the second sensor to operate in an active mode, (b) operating the second sensor to obtain data indicative of whether an eye is proximate to the wearable device, and (c) determining, based on the data indicative of whether an eye is proximate, whether or not the wearable device is being worn;

if it is determined that the wearable device is not being worn, then continuing operation of the wearable device in the first state; and

otherwise, if it is determined that the wearable device is being worn, then causing the wearable device to switch to operation in a second state.

2. The method of claim 1 , further comprising:

based on the wearable device being worn, causing the wearable device to operate in a second state, wherein the wearable device is configured to execute additional functionality in the second state as compared to the first state; and

based on the wearable device not being worn, causing the wearable device to operate in the first state.

3. The method of claim 1 , further comprising:

based on the wearable device being worn, causing the wearable device to operate in a second state, wherein the wearable device is configured to consume more power in the second state than in the first state; and

based on the wearable device not being worn, causing the wearable device to operate in the first state.

4. The method of claim 1 , further comprising:

based on the wearable device being worn, causing the wearable device to operate in a second state, wherein the wearable device is configured to be unlocked in the second state, and wherein the wearable device being configured to be unlocked comprises the wearable device being configured to be responsive to a plurality of inputs; and

based on the wearable device not being worn, causing the wearable device to operate in the first state, wherein the wearable device is locked in the first state, and wherein the wearable device being configured to be locked comprises the wearable device being configured to be unresponsive to at least one of the plurality of inputs.

5. The method of claim 1 , wherein the wearable device being worn comprises the wearable device being worn on a face of a user.

6. The method of claim 1 , wherein determining, based on the data from the second sensor, whether the wearable device is being worn comprises:

comparing the data from the second sensor to a predetermined threshold, wherein the predetermined threshold is based on a minimum value detected by the second sensor when the wearable device is being worn;

based on the data from the second sensor being greater than the predetermined threshold, determining that the wearable device is being worn; and

based on the data from the second sensor being less than the predetermined threshold, determining that the wearable device is not being worn.

7. The method of claim 1 , wherein determining, based on the data from the second sensor, whether the wearable device is being worn comprises:

comparing the data from the second sensor to a characteristic signal shape, wherein the characteristic signal shape is based on a signal shape detected by the second sensor when the wearable device is being worn;

based on the data from the second sensor being substantially similar to the characteristic signal shape, determining that the wearable device is being worn; and

based on the data from the second sensor not being substantially similar to the characteristic signal shape, determining that the wearable device is not being worn.

8. The method of claim 1 , wherein:

the second sensor being configured in the idle mode comprises the second sensor being powered down; and

triggering the second sensor to operate in the active mode comprises (i) powering on the second sensor and (ii) requesting the data from the second sensor.

9. The method of claim 1 , wherein the second sensor operating in the active mode comprises the second sensor (i) being powered on, (ii) collecting the data, and (iii) providing the data to the HMD.

10. The method of claim 1 , wherein the second sensor is arranged on the wearable device, and the first sensor is arranged on another computing device that is communicatively coupled to the wearable device.

11. The method of claim 10 , wherein the first sensor is a touchscreen on a mobile phone tethered to the wearable device.

12. A non-transitory computer readable medium having stored therein instructions that, when executed by a processor, cause the processor to perform functions comprising:

while a wearable device is operating in a first state and a first sensor is operating in an active mode:

initially operating an inward-facing second sensor in an idle mode; and

receiving an indication of a touch input at the first sensor;

the first sensor is operating in an active mode, receiving an indication of a touch input at the first sensor;

in response to receiving the indication of the touch input: (a) triggering the second sensor to operate in an active mode, (b) operating the second sensor to obtain data indicative of whether an eye is proximate to the wearable device, and (c) determining, based on the data indicative of whether an eye is proximate, whether or not the wearable device is being worn;

if it is determined that the wearable device is not being worn, then continuing operation of the wearable device in the first state; and

otherwise, if it is determined that the wearable device is being worn, then causing the wearable device to switch to operation in a second state.

13. The non-transitory computer readable medium of claim 12 , wherein the functions further comprise:

based on the wearable device being worn, causing the wearable device to operate in a second state, wherein the wearable device is configured to execute additional functionality in the second state as compared to the first state; and

based on the wearable device not being worn, causing the wearable device to operate in the first state.

14. The non-transitory computer readable medium of claim 12 , wherein the functions further comprise:

based on the wearable device being worn, causing the wearable device to operate in a second state, wherein the wearable device is configured to consume more power in the second state than in the first state; and

based on the wearable device not being worn, causing the wearable device to operate in the first state.

15. The non-transitory computer readable medium of claim 12 , wherein the functions further comprise:

based on the wearable device being worn, causing the wearable device to operate in a second state, wherein the wearable device is configured to be unlocked in the second state, and wherein the wearable device being configured to be unlocked comprises the wearable device being configured to be responsive to a plurality of inputs; and

based on the wearable device not being worn, causing the wearable device to operate in the first state, wherein the wearable device is locked in the first state, and wherein the wearable device being configured to be locked comprises the wearable device being configured to be unresponsive to at least one of the plurality of inputs.

16. The non-transitory computer readable medium of claim 12 , wherein the second sensor is arranged on the wearable device, and wherein the first sensor is arranged on another computing device that is communicatively coupled to the wearable device.

17. The non-transitory computer readable medium of claim 12 , wherein the first sensor is a touchscreen on a mobile phone tethered to the wearable device.

18. A wearable computing device comprising:

a communication interface operable for communication with another computing device, wherein the other computing device comprises a first sensor;

a second sensor, wherein the second sensor is arranged as inward-facing on the wearable computing device such that to the second sensor is operable to obtain data indicative of whether an eye is proximate to the wearable computing device when the wearable computing device is worn;

a processor; and

data storage comprising instructions executable by the processor to carry out functions including:

while the wearable computing device is operating in a first state and the first sensor is operating in an active mode:

(i) initially operating the first sensor in an active mode and the inward-facing second sensor in an idle mode,

(ii) receiving an indication of a touch input at the first sensor,

(iii) in response to receiving the indication of the touch input: (a) triggering the second sensor to operate in an active mode, (b) operating the second sensor to obtain data indicative of whether an eye is proximate to the wearable device, and (c) determining, based on the data indicative of whether an eye is proximate, whether the HMD is being worn;

if it is determined that the wearable device is not being worn, then continuing operation of the wearable device in the first state; and

otherwise, if it is determined that the HMD is being worn, then causing the wearable device to switch to operation in a second state.

19. The wearable computing device of claim 18 , wherein the first sensor comprises a capacitive sensor.

20. The wearable computing device of claim 18 , wherein the second sensor comprises a camera.

21. The wearable computing device of claim 18 , wherein the other computing device comprises a mobile phone tethered to the wearable device.