Magnetic Crown Assembly for Sealed Wearable Control Input
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Solution Overview
Problem
Conventional wearable devices with rotatable buttons or crowns that extend through the housing compromise the ability to seal the interior, exposing internal components to the external environment.
Innovation Solution
A control button assembly with a magnetically actuated mechanism, where a magnet is rotated externally and detected by a Hall effect sensor within the housing, ensuring the button does not penetrate the housing, thus maintaining a sealed interior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rotatable button or crown extends through the housing into the interior, then the user can interact with the device controls, but the interior of the housing cannot be securely sealed, exposing internal components to the external environment
Solution Approach 1:
The control button assembly is segmented into separate functional components: the crown (user interface) remains external while the sensing mechanism (magnet and Hall effect sensor) is positioned internally without penetrating the housing. This segmentation allows the housing to maintain its sealing integrity while still enabling control functionality through non-contact magnetic field detection.
Solution Approach 2:
A magnetic field is introduced as an intermediary between the external crown and the internal sensing mechanism. The magnet rotates with the crown externally, and its rotational position is detected by the Hall effect sensor internally through the housing wall, eliminating the need for physical penetration while maintaining functional coupling.
2Adaptability or versatility
If a rotatable button extends through the housing, then control functionality is achieved, but internal components are exposed to environmental factors like water and pressure
Solution Approach 1:
The magnetic field serves as an intermediary that transmits rotational information from the external crown to the internal sensor without requiring a physical pathway through the housing. This eliminates the vulnerability point where environmental factors could penetrate, while maintaining full control functionality.
Solution Approach 2:
The mechanical system of physical penetration and direct contact is replaced with a magnetic field-based sensing system. The magnet and Hall effect sensor enable rotational detection through non-contact means, substituting mechanical coupling with electromagnetic coupling that does not compromise the housing seal.
3Reliability
If the control button assembly does not extend through the housing, then the interior remains sealed, but the user interface must be positioned externally without direct internal sensing
Solution Approach 1:
The magnetic field intermediary enables simple positioning of the sensing mechanism. The magnet can be placed on the external crown and the Hall effect sensor on the internal surface of the housing, with the magnetic field naturally bridging the gap through the housing wall without requiring complex routing or penetration mechanisms.
Solution Approach 2:
The magnetic field automatically penetrates the housing wall without requiring any modification to the housing structure. The housing wall itself becomes transparent to the magnetic field, allowing the sensing mechanism to self-configure with the magnet externally and sensor internally, eliminating the need for complex sealing arrangements around penetrating components.
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 provides a sealed and durable wearable device capable of withstanding environmental challenges like water ingress and pressure, ensuring reliable operation in demanding conditions.
Implementation Method 1
The Hall effect sensor is communicatively coupled with the controller and configured to generate control signals for use by the controller to control functionality of the device. Upon the magnet being rotated via rotation of the crown, the Hall effect sensor is configured to detect the rotation of the magnet.
Data Source
AI summary
A wearable electronic device comprising a housing. The device additionally comprises a Hall effect sensor enclosed within an interior of the housing and positioned adjacent to or engaged with an interior surface of the housing. The device further comprises a control button assembly engaged with the housing. An exterior of the housing presents a cavity in which at least a portion of the control button assembly is received. A proximal end of the control button assembly comprises a magnet. A distal end of the control button assembly comprises a crown that is rotatable with respect to the housing, and the control button assembly is configured such that rotation of the crown causes a corresponding rotation of the magnet. The housing comprises a sidewall, and the sidewall entirely separates the control button assembly from the Hall effect sensor.