Wristwatch Power Mode Switching Through Accelerometer Wrist-Turn Detection

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Solution Overview

Problem

Existing methods for switching devices like wristwatches into different power modes struggle to reliably distinguish between intentional commands and other gestures or accelerations, leading to unwanted power mode changes and increased power consumption.

Innovation Solution

A method using a combination of an accelerometer with embedded signal processing and a touch panel to detect gestures, employing criteria such as frequency, direction, and slope of acceleration signals to discriminate between valid gestures like taps and other movements, thereby reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an accelerometer with amplitude-based threshold detection is used to detect gestures, then the device can respond to user input, but it cannot reliably distinguish between intentional taps and normal acceleration during sport or cloth contact, causing unwanted power mode switches

Engineering Contradiction:
Improvegesture detection accuracyVSAvoidunwanted power mode switches
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the detection parameters from simple amplitude threshold to a combination of frequency range (5-150 Hz) and slope criteria. This parameter transformation allows the system to distinguish between intentional taps (which produce specific frequency and slope characteristics) and normal accelerations during sport or cloth contact (which have different frequency and slope profiles), thereby improving gesture detection reliability and reducing unwanted power mode switches.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the display is switched to sleeping mode to reduce power consumption, then battery life is extended, but the device responds slower to user activation commands

Engineering Contradiction:
Improvepower consumptionVSAvoidactivation response time
Core Design Contradiction:
Use of energy by moving objectVSSpeed

Solution Approach 1:

The system performs preliminary action by continuously monitoring acceleration signals even when the display is in sleeping mode. The accelerometer remains active and pre-processes signals to detect tap gestures, so when a tap is detected, the display can be activated immediately without the delay of waking from deep sleep. This preliminary monitoring enables fast activation response while maintaining low power consumption during idle periods.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If a touch panel is used alone to detect gestures, then the system can detect user input, but it cannot distinguish between intentional commands and accidental touches or environmental interference

Engineering Contradiction:
Improvegesture detection capabilityVSAvoidcommand accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent merges the detection capabilities of the accelerometer and touch panel into a unified gesture detection system. The accelerometer detects the mechanical impact and acceleration patterns of intentional taps, while the touch panel detects the actual contact with the glass surface. By combining these two independent detection mechanisms, the system achieves high reliability in distinguishing intentional commands from accidental touches or environmental interference, as both sensors must confirm the gesture simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4600760A1A method and circuit for switching a wristwatch from a first power mode to a second power mode
Publication Date: 2025.08.13 SLYDE ANALYTICS LLC
  • EP4600760A1 patent drawingFigure 1a
  • EP4600760A1 patent drawingFigure 1b
  • EP4600760A1 patent drawingFigure 2

AI summary

A method for switching a wristwatch (1) from a first power mode to a second power mode, comprising: using an accelerometer (23) for detecting a wristturn, and switching said wristwatch (1) from said first power mode to said second power mode when a wristturn has been detected, wherein said step of detecting a wristturn comprises: detecting that an orientation of the wristwatch (1) is in a starting position, wherein said step of detecting that the orientation is in the starting position comprises detecting that the orientation of the wristwatch (1) is held within a first range for a defined time; detecting that an orientation of the wristwatch (1) is then in a final position, wherein said step of detecting that the orientation is in the final position comprises detecting that the orientation is in a second range different from said first range, and in response to a detection that the orientation of the wristwatch (1) is in the second range, detecting that the wristwatch (1) remains substantially immobile during a predetermined duration.