Self-learning wireless thermostat that minimizes battery drain

1. A method of controlling signal transmission in a building control system, the method comprising:

measuring a plurality of signal values associated with an environmental variable using a sensor of a wireless device;

dynamically determining, by the wireless device, a noise threshold based on the plurality of signal values;

combining a first signal value and a second signal value of the plurality of signal values using a mathematical relationship to determine a result associated with the first signal value and the second signal value; and

periodically transmitting the first signal value from the wireless device to a controller in response to the result exceeding the noise threshold;

wherein the environmental variable is a temperature.

2. The method of claim 1 , wherein the wireless device is a thermostat.

3. The method of claim 1 , wherein the wireless device is a battery operated device.

4. The method of claim 1 , wherein the controller applies the first signal value as input to a control algorithm that operates to control the environmental variable.

5. The method of claim 1 , wherein the noise threshold is a dynamic noise threshold that changes over time based on subsequent measurements of the environmental variable, wherein the dynamic noise threshold models a level of signal noise present in the plurality of signal values over time.

6. The method of claim 1 , wherein the result is a difference between the first signal value and the second signal value.

7. The method of claim 1 , wherein the result is a ratio between the first signal value and the second signal value.

8. A wireless device, comprising:

a sensor configured to measure an environmental variable;

a wireless radio configured to wirelessly transmit a message; and

a processing circuit having a processor and memory, the memory storing instructions that, when executed by the processor, cause the processing circuit to:

receive, from the sensor, a plurality of signal values associated with the environmental variable;

dynamically determine a noise threshold based on the plurality of signal values;

combine a first signal value and a second signal value of the plurality of signal values using a mathematical relationship to determine a result associated with the first signal value and the second signal value; and

cause the wireless radio to transmit the first signal value in response to the result exceeding the noise threshold;

wherein the environmental variable is a temperature.

9. The wireless device of claim 8 , wherein the wireless radio transmits the first signal value to a controller.

10. The wireless device of claim 9 , wherein the controller applies the first signal value as input to a control algorithm that operates to control the environmental variable.

11. The wireless device of claim 8 , wherein the wireless device is a thermostat.

12. The wireless device of claim 8 , wherein the wireless device is battery operated.

13. The wireless device of claim 8 , wherein the noise threshold is a dynamic noise threshold that changes over time based on subsequent measurements of the environmental variable, wherein the dynamic noise threshold models a level of signal noise present in the plurality of signal values over time.

14. The wireless device of claim 8 , wherein the result is a difference between the first signal value and the second signal value.

15. The wireless device of claim 8 , wherein the result is a ratio between the first signal value and the second signal value.

16. A building management system (BMS), comprising:

a controller configured to control an environmental variable of a building; and a wireless device configured to:

measure a plurality of signal values associated with the environmental variable;

dynamically determine a noise threshold based on the plurality of signal values;

combine a first signal value and a second signal value of the plurality of signal values using a mathematical relationship to determine a result associated with the first signal value and the second signal value; and

transmit the first signal value to the controller in response to the result exceeding the noise threshold;

wherein the environmental variable is a temperature.

17. The building management system (BMS) of claim 16 , wherein in response to receiving the first signal value from the wireless device, the controller is further configured to apply the first signal value as input to a control algorithm that operates to control the environmental variable of the building.

18. The building management system (BMS) of claim 16 , wherein the wireless device is a thermostat.

19. The building management system (BMS) of claim 18 , wherein the thermostat is battery operated.

20. The building management system (BMS) of claim 19 , wherein the first signal value is a current measurement of the temperature and the second signal value is a past measurement of the temperature.

21. The building management system (BMS) of claim 16 , wherein the noise threshold is a dynamic noise threshold that changes over time based on subsequent measurements of the environmental variable, wherein the dynamic noise threshold models a level of signal noise present in the plurality of signal values over time.

22. The building management system (BMS) of claim 16 , wherein the result is a difference between the first signal value and the second signal value.

23. The building management system (BMS) of claim 16 , wherein the result is a ratio between the first signal value and the second signal value.