Self-powered devices and methods

1. A self-powered device, the device comprising:

an energy collector configured to collect energy to power the self-powered device from an environment surrounding the self-powered device;

a processor; and

a memory comprising:

instructions for selecting one of a plurality of modes of operation, wherein the plurality of modes of operation include: (i) a low-power mode of operation in which the self-powered device consumes less than a pre-determined or adaptively-determined amount of power and the self-powered device has less than full functionality, and (ii) and a high-power mode of operation in which the self-powered device consumes more than the pre-determined or adaptively-determined amount of power and the self-powered device has more functionality than in the low-power mode wherein the instructions for selecting one of a plurality of modes of operation include instructions for conserving power by alternating between the low-power mode of operation and the high-power mode of operation.

2. The self-powered device of claim 1 , wherein the instructions for selecting one of a plurality of modes of operation are configured to: (a) select the low-power mode of operation when available energy becomes insufficient to fully power the self-powered device, and (b) select the high-power mode of operation when energy greater than a threshold is available.

3. The self-powered device of claim 1 , further comprising a display, wherein said functionality includes the functionality of the display.

4. The self-powered device of claim 3 , wherein during low-power mode, the instructions for selecting one of a plurality of modes are configured to, in at least one of the modes, perform one of: turn the display off, dim the display, operate the display at a reduced contrast, operate the display at a reduced refresh rate, and operate the display with different encoding/decoding parameters.

5. The self-powered device of claim 1 , further comprising instructions to: display a subset of database information; display meeting room information; display examination room information in a hospital or doctor's office; display news, advertising, or market information; display pricing or other product status information; display room status information; or display the average wait for customers on hold, the number of customers presently being served, or whether the wait time is increasing.

6. The self-powered device of claim 1 , further comprising instructions to display scheduling information.

7. The self-powered device of claim 1 , wherein the instructions for selecting one of a plurality of modes of operation are further configured to reduce oscillatory transitions between the low-power mode of operation and the high-power mode of operation by taking into account a predetermined amount of hysteresis.

8. The self-powered device of claim 1 , wherein the instructions for selecting one of a plurality of modes of operation is configured to initiate a series of prioritized shutdowns of partial or entire subsystems of the self-powered device.

9. The self-powered device of claim 1 , further comprising one or more physical-layer networking subsystems, wherein the instructions for selecting one of a plurality of modes of operation is configured to selectively shut down some or all of the physical-layer networking subsystems.

10. The self-powered device of claim 1 , further comprising a proximity sensor, wherein the instructions for selecting one of a plurality of modes of operation is configured to transition from the low-power mode of operation to the high-power mode of operation when the proximity sensor detects the presence of a user near the self-powered device.

11. The self-powered device of claim 1 , wherein the instructions for selecting one of a plurality of modes of operation is configured to transition between modes of operation at predetermined time slots.

12. The self-powered device of claim 1 , wherein the instructions for selecting one of a plurality of modes of operation is configured to allow the self-powered device to communicate with another device in a network only within a predetermined time slot.

13. The self-powered device of claim 1 , wherein the instructions for selecting one of a plurality of modes of operation is configured to transition to the low-power mode of operation based on at least one scheduled “night” period.

14. The self-powered device of claim 1 , wherein the low-power mode of operation is a sleep mode.

15. A self-powered device configured to be powered by energy collected from a surrounding environment, the self-powered device comprising:

an energy collector configured to collect energy to power the self-powered device from a surrounding environment in which the self-powered device is located;

a processor; and

a memory comprising:

instructions for selecting one of a plurality of modes of operation, wherein the plurality of modes of operation include:

(i) a low-power mode of operation in which the self-powered device consumes less than a pre-determined or adaptively-determined amount of power and the self-powered device uses less than its full capabilities, and

(ii) and a high-power mode of operation in which self-powered device consumes more than the pre-determined or adaptively-determined amount of power and the self-powered device uses its full capabilities,

wherein the instructions for selecting one of a plurality of modes of are configured to:

(a) select the low-power mode of operation when available energy becomes insufficient to fully power the self-powered device; and

(b) select the high-power mode of operation when energy greater than a threshold is available.

16. A method for managing power consumption of a self-powered device, the method comprising:

collecting energy to power a self-powered device from an environment surrounding the self-powered device;

selecting a low-power mode of operation available energy becomes insufficient to fully power the self-powered device, where the low-power mode of operation is a mode of operation in which the self-powered device consumes less than a pre-determined or adaptively-determined amount of power and the self-powered device has less than full functionality, when; and

selecting a high-power mode of operation when energy greater than a threshold is available, where the high-power mode of operation is a mode of operation in which the self-powered device consumes more than the pre-determined or adaptively-determined amount of power and the self-powered device has more functionality than in the low-power mode.

17. A method of claim 16 , further comprising communicating with a remote computing device only during the high-power mode of operation.

18. A method of claim 16 , wherein the selecting further comprises:

(a) selecting the low-power mode of operation when available power from a energy collector becomes insufficient to keep the self-powered device fully powered, and

(b) selecting the high-power mode of operation when energy greater than a threshold is available.