Mesh routing of sleepy sensor data
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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 requiring frequent maintenance, and increased costs from designing and manufacturing different versions with user interfaces.
Innovation Solution
The implementation of a method to detect excessive sleep current draw in battery-powered HVAC devices using a MOSFET and transistor circuit, which generates a trigger signal and interrupts the microcontroller to transmit a fault signal, along with an energy-efficient mesh network method that minimizes wake-up times and delegates destination address determination to routers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wireless HVAC devices use battery power 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 peer-to-peer mesh networking where devices automatically route data for each other without requiring centralized coordination or manual configuration. End nodes can communicate directly with destination nodes through intermediate router nodes, eliminating the need for frequent maintenance interventions.
2Reliability
If battery-powered devices wake up frequently to check for messages, then message delivery reliability is improved, but power consumption increases
Solution Approach 1:
The system performs preliminary action by having sending nodes transmit data to router nodes before the receiving end node wakes up. Router nodes store and forward this data when the end node becomes active, eliminating the need for frequent wake-up cycles while ensuring reliable message delivery.
Solution Approach 2:
Router nodes act as intermediaries between sending and receiving end nodes. These routers buffer and forward data packets, allowing end nodes to remain in low-power sleep mode longer while maintaining reliable communication through the mesh network infrastructure.
3Device complexity
If end nodes determine destination addresses directly, then device complexity is reduced, but network efficiency decreases
Solution Approach 1:
The system segments the address determination function by separating end nodes from router nodes. End nodes have simplified functionality for sending and receiving data, while router nodes handle the complex task of destination address determination and routing decisions, optimizing overall network efficiency.
Solution Approach 2:
Router nodes serve as intermediaries that handle destination address determination. This allows end nodes to remain simple devices without complex routing logic, while the network maintains high efficiency through intelligent routing at the router level.
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.