Battery-Powered HVAC Sensor Sleep Current Detection and Mesh Routing
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Solution Overview
Problem
Existing wireless HVAC systems face challenges with high installation costs due to hard-wiring, limited battery lifespan in wireless devices, and increased manufacturing costs due to the need for various device versions with user interfaces, which affect reliability and efficiency.
Innovation Solution
A method and circuit for detecting excessive sleep current draw in battery-powered HVAC devices using a MOSFET and transistor configuration to generate interrupts and fault signals, and an energy-efficient mesh network method for data transmission that minimizes power consumption by optimizing sleep and awake modes, along with a kit for manufacturing HVAC sensors with reversible printed circuit boards for exposed or hidden displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wireless HVAC devices use batteries to eliminate hard-wiring, then installation cost and complexity are reduced, but battery lifespan is limited and requires periodic maintenance
Solution Approach 1:
The system enables self-service through automated mesh networking where devices automatically discover and route data through neighboring devices without manual configuration or intervention, eliminating the need for hard-wiring while maintaining reliable communication
Solution Approach 2:
The patent applies universal battery-powered wireless device architecture that can function in multiple HVAC applications (thermostats, sensors, controllers) without requiring application-specific hard-wiring, making the solution broadly applicable while managing power consumption through sleep modes
2Reliability
If battery-powered devices operate continuously in awake mode to ensure reliable data transmission, then data transmission reliability is improved, but power consumption increases and battery life decreases
Solution Approach 1:
The system implements periodic wake-sleep cycles where devices periodically wake to transmit or receive data, then return to sleep mode. The mesh network buffers and forwards data during sleep periods, maintaining reliability while dramatically reducing average power consumption compared to continuous operation
Solution Approach 2:
The mesh network acts as an intermediary by buffering data at intermediate nodes and forwarding it when the target device is asleep, enabling reliable data transmission without requiring the receiving device to remain continuously awake
3Adaptability or versatility
If different versions of wireless devices are manufactured to include or exclude user interfaces, then customer customization needs are met, but manufacturing costs increase and profits decrease
Solution Approach 1:
The patent describes a universal wireless device platform that can operate with or without user interface components, allowing manufacturers to produce a base model and optional accessories rather than entirely different device versions, reducing tooling and testing costs while maintaining flexibility
Solution Approach 2:
The device architecture segments the user interface as an optional separate component that can be added or omitted, allowing the core wireless HVAC functionality to be manufactured once and configured differently through software or optional hardware attachments
4Device complexity
If sleep current draw is not monitored, then device complexity is reduced, but excessive current draw during sleep mode reduces battery life undetected
Solution Approach 1:
The sleep current monitoring circuit automatically detects excessive current draw and generates interrupt signals without requiring software-based monitoring, enabling the system to self-diagnose and alert users to battery drain issues while adding minimal complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution extends battery life, reduces manufacturing costs, and enhances reliability by detecting excessive current draw, optimizing power usage in HVAC devices, and simplifying sensor manufacturing configurations.
Implementation Method 1
measuring a voltage drop across a MOSFET device coupled in a forward-conducting orientation in series between the battery and the microcontroller
Implementation Method 2
causing a transistor to conduct when the voltage drop exceeds a predetermined threshold to generate a first trigger signal
Data Source
AI summary
HVAC components having improved efficiency are described. In one embodiment, excessive sleep current draw in a battery-powered device having a microcontroller is detected by measuring a voltage drop across a MOSFET device coupled in a forward-conducting orientation in series between the battery and the microcontroller, causing a transistor to conduct when the voltage drop exceeds a predetermined threshold to generate a first trigger signal, integrating the first trigger signal to generate a second trigger signal, and generating an interrupt to the microcontroller. In another embodiment, a battery-saving method of operating an HVAC component includes maintaining the HVAC device in the sleep mode, receiving a user input to wake the device, transmitting a data request and returning the HVAC component to the sleep mode, waking up the HVAC device to poll an adjacent network node storing a cached response, displaying the response, and returning the HVAC device to sleep.