Conditional retrieval

1. A sensor reader device, comprising:

a wireless communication interface;

a processor; and

a computer-readable medium including instructions that, when executed by the processor, cause the reader to perform a set of functions comprising:

detecting that a sensor device adapted to measure a biological signal as sensor data is within wireless communication range of the sensor reader device;

retrieving, using the wireless communication interface and from the detected sensor device, a first set of data, wherein the first set of data includes at least one of an indication of an amount of energy available from a power supply of the sensor device and an indication of an amount of sensor data retrievable by the sensor reader device from the sensor device;

using the first set of data to determine that a condition has been satisfied comprising using the first set of data to determine that at least a threshold amount of energy is available from the power supply or that the amount of sensor data retrievable by the sensor reader device from the sensor device is less than a threshold amount of sensor data; and

responsive to determining that the condition has been satisfied, retrieving, using the wireless communication interface and from the detected sensor device a second set of data, wherein the second set of data comprises the sensor data measured by the sensor device.

2. The sensor reader device of claim 1 , wherein the first set of data includes an indication of an amount of energy available from the power supply.

3. The sensor reader device of claim 2 , wherein using the first set of data to determine that a condition has been satisfied comprises:

using the first set of data to determine that at least a threshold amount of energy is available from the power supply.

4. The sensor reader device of claim 2 , wherein the power supply comprises a battery, and wherein the indication of the amount of energy available from the power supply comprises an indication of an amount of energy stored in the battery.

5. The sensor reader device of claim 2 , wherein the power supply comprises a photovoltaic cell, and wherein the indication of the amount of energy available from the power supply comprises an indication of an amount of energy available from the photovoltaic cell.

6. The sensor reader device of claim 1 , wherein the first set of data includes an indication of an amount of sensor data retrievable by the sensor reader device from the sensor device.

7. The sensor reader device of claim 6 , wherein using the first set of data to determine that a condition has been satisfied comprises:

using the first set of data to determine that less than a threshold amount of sensor data is retrievable by the sensor reader device from the sensor device.

8. The sensor reader device of claim 1 , wherein using the first set of data to determine that a condition has been satisfied comprises:

using the first set of data to determine that at least a threshold amount of energy is available from the power supply and that the amount of sensor data retrievable by the sensor reader device from the sensor device is less than a threshold amount of sensor data.

9. The sensor reader device of claim 1 , wherein using the first set of data to determine that a condition has been satisfied comprises:

using the first set of data to determine that the sensor device is able to transmit the sensor data to the sensor reader device in a single communication session.

10. The sensor reader device of claim 1 , wherein the sensor data comprises data indicative of an analyte concentration.

11. The sensor reader device of claim 1 , wherein the wireless communication interface comprises an antenna.

12. The sensor reader device of claim 1 , wherein the wireless communication interface comprises a photodetector.

13. The sensor reader device of claim 1 , wherein the sensor device is a body-mountable device.

14. The sensor reader device of claim 1 , wherein the sensor device is an eye-mountable device.

15. The sensor reader device of claim 1 , wherein detecting that the sensor device is within wireless communication range of the sensor reader device comprises:

transmitting a query message to the sensor device; and

receiving an acknowledgement message from the sensor device.

16. A sensor device, comprising:

a power supply;

a wireless communication interface;

a sensor adapted to measure a biological signal as sensor data;

a logic component configured to perform a set of functions comprising:

communicating through the wireless communication interface to notify a sensor reader device that the sensor device is within communication range of the wireless communication interface;

sending, via the wireless communication interface, a first set of data to the sensor reader device to demonstrate capability of sending the sensor data in a single communication session, wherein the first set of data includes an indication of an amount of energy available from the power supply and an indication of an amount of sensor data retrievable by the sensor reader device from the sensor device; and

responsive to a request from the sensor reader device in response to the first set of data, sending, via the wireless communication interface, a second set of data, wherein the second set of data comprises the sensor data.

17. The sensor device of claim 16 , wherein the first set of data includes an indication of an amount of energy available from the power supply.

18. The sensor device of claim 16 , wherein the first set of data includes an indication of an amount of sensor data retrievable by the sensor reader device from the sensor device.

19. The sensor reader device of claim 1 , wherein the threshold amount of energy or the threshold amount of sensor data may vary based on a sensor device configuration or a sensor reader device configuration.