Determining rotation using sensor displaced from magnet
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Solution Overview
Problem
Existing HVAC controllers struggle to accurately determine the absolute rotational position of dials, which hinders precise control of environmental parameters such as temperature based on user inputs.
Innovation Solution
The HVAC controller employs a Hall effect sensor and a magnet located on a gear that rotates with the dial, allowing for precise determination of the dial's absolute rotational position over time, using a configuration where the Hall effect sensor is displaced from the magnet, enabling accurate control of HVAC components based on dial rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnet with multiple pole pairs is used to improve rotational position measurement precision, then measurement precision is improved, but the magnet size increases making it difficult to fit within the housing
Solution Approach 1:
The patent changes the physical parameters of the magnet by using a single pole pair instead of multiple pole pairs, reducing the magnet size to fit within the housing while compensating for the reduced measurement precision through signal processing techniques and geometric relationships in the Hall effect sensor output
Solution Approach 2:
The patent introduces asymmetry by displacing the Hall effect sensor from the center of the magnet, creating an off-center configuration that allows accurate rotational position measurement with a single pole pair magnet, resolving the contradiction between measurement precision and magnet size
2Measurement precision
If the Hall effect sensor is located on or within the magnet, then measurement precision is improved, but the device complexity and housing space requirements increase
Solution Approach 1:
The patent extracts the Hall effect sensor from the magnet structure, placing it at a displaced location outside the magnet. This separation simplifies the overall device configuration and reduces housing space requirements while maintaining measurement precision through the geometric relationship between the sensor position and magnet rotation
3Ease of manufacture
If a magnet with a single pair of poles is used to reduce housing size, then ease of manufacture and housing space are improved, but measurement precision deteriorates
Solution Approach 1:
The patent uses asymmetry by positioning the Hall effect sensor at a displaced location rather than at the center of the magnet. This asymmetric configuration enables the system to achieve accurate rotational position measurement with a simple single pole pair magnet, simultaneously improving ease of manufacture and maintaining measurement precision
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
This configuration enables precise control of HVAC parameters by tracking the rotational position of the dial, ensuring accurate temperature regulation and enhancing user interface functionality.
Implementation Method 1
a sensor configured to generate an electrical signal which indicates a rotational position of the magnet
Data Source
AI summary
A device may be configured to control a heating, ventilation, and air conditioning (HVAC) system within a building. The device includes a rotatable dial comprising a first gear; a second gear configured to engage with the first gear, wherein a rotation of the first gear causes the second gear to rotate; a magnet placed on the second gear, wherein the magnet rotates with the second gear; a sensor configured to generate an electrical signal which indicates a rotational position of the magnet, wherein the rotational position of the magnet indicates the rotational position of the second gear; and processing circuitry. The processing circuitry is configured to receive, from the sensor, the electrical signal which indicates the rotational position of the second gear; and change a temperature set point based on a change in the rotational position of the second gear.