Thermostat RF Receiver Periodic Polling Battery Life
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Solution Overview
Problem
Remote controllable thermostats face significant battery life reduction due to high power demands from radio communications and mode switch monitoring, necessitating the use of costly lithium-ion batteries or constant AC power, which is not always available.
Innovation Solution
A remote controllable thermostat with an onboard power supply using low voltage, low cost alkaline batteries, featuring a microcontroller that manages power conservation by periodically activating the RF receiver, disconnecting it during quiescent states, and employing a sleep mode polling schedule to minimize power consumption, along with a boost regulator circuit to optimize power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless radio communications (WiFi/RF) are used for remote control, then ease of operation is improved, but power consumption increases and battery life is reduced
Solution Approach 1:
The patent implements periodic polling where the microcontroller wakes up at predetermined intervals to check for remote control commands, then returns to sleep mode. This periodic activation of the radio receiver allows the system to maintain wireless remote control capability while dramatically reducing power consumption compared to continuous operation.
2Speed
If continuous radio receive monitoring is implemented, then response time to remote commands is improved, but battery life is reduced
Solution Approach 1:
The system uses periodic polling at predetermined time intervals to check for incoming remote commands. While not continuous monitoring, this approach provides a practical balance between response time and power consumption, allowing the thermostat to wake up, check for commands, and return to sleep mode.
Solution Approach 2:
The microcontroller is programmed with predetermined polling intervals before operation begins. This preliminary setup establishes the timing schedule for wake-up events, ensuring the system is ready to receive commands at regular intervals without requiring complex real-time decision-making during operation.
3Measurement precision
If mode switch monitoring is continuously performed, then control precision is improved, but power consumption increases
Solution Approach 1:
The microcontroller reads the state of mode selector switches only during its periodic wake-up intervals rather than continuously monitoring them. This periodic sampling maintains adequate control precision for HVAC operation while significantly reducing the power consumption associated with continuous switch monitoring.
4Reliability
If both AC power and battery power sources are available, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements an automatic power source selection system where the microcontroller monitors the presence of AC power and automatically switches between AC and battery power sources without user intervention. The system also automatically manages battery disconnection when AC power is available, providing self-service power management that reduces the perceived complexity for users while maintaining reliable dual-power operation.
Data Source
AI summary
A remote controllable thermostat has an on-board power supply with batteries, a microcontroller having a timer, a temperature sensor, a temperature set point control controller and an RF receiver. The thermostat also has HVAC state control means for generating HVAC control signals in response to sensed temperatures being outside of control set point range and for periodically connecting and disconnecting the RF receiver from the power source to conserve battery power. Where the thermostat has user mode selector switches, the microcontroller is further programmed to read their state only periodically for additional battery power conversation.