Motion-Based Device Wake-Up Using ToF Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic devices face increased power consumption due to false wake-ups when sensors detect users passing by, leading to unnecessary activation of displays, which reduces battery life and contradicts the purpose of sleep mode.
Innovation Solution
Implementing a time of flight (ToF) sensor to detect and differentiate between a user approaching the device and a user passing by, using a threshold distance value and a period of detection to accurately determine if the user is approaching, thereby preventing false wake-ups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the display uses a sensor to wake up when a user is detected, then the wake-up time is improved, but false wake-ups occur when a user passes by, increasing power consumption
Solution Approach 1:
The system dynamically evaluates the motion state of detected objects by analyzing distance changes across multiple frames. Instead of a static presence detection, the system continuously monitors whether the object is approaching or moving away, adapting the wake-up decision based on the dynamic motion pattern. This resolves the contradiction by adding temporal dimension to detection, allowing the system to distinguish between intentional approach (wake up) and passing by (remain in sleep mode).
Solution Approach 2:
The system implements feedback by continuously monitoring distance values across multiple frames and using this information to adjust the wake-up decision. The controller receives feedback from the sensor about the object's position and motion state, and uses this feedback to determine whether to activate the display. This feedback mechanism prevents false wake-ups by verifying that the detected object is indeed approaching the device before triggering wake-up, thus reducing unnecessary power consumption while maintaining fast response to legitimate user presence.
2Ease of operation
If the display wakes up based on user presence detection, then the user experience is improved, but the battery life is reduced due to frequent false wake-ups
Solution Approach 1:
The system transitions from static presence detection to dynamic motion analysis by evaluating distance changes across multiple frames. The controller determines whether an object is approaching or moving away based on temporal variation in distance measurements. This dynamic approach improves user experience by ensuring the display wakes up only when a user intentionally approaches, while simultaneously extending battery life by preventing false wake-ups from passing-by objects.
Solution Approach 2:
The system performs preliminary analysis of motion patterns before executing the wake-up action. By analyzing distance changes across multiple frames in advance, the system preliminarily determines whether the detected object represents a legitimate user approach warranting wake-up. This preliminary action filters out false positives before the costly wake-up operation occurs, thereby extending battery life while maintaining good user experience for genuine interactions.
3Speed
If the system continuously monitors for user presence, then the wake-up responsiveness is improved, but the power consumption increases
Solution Approach 1:
The system employs periodic action by monitoring distance values at discrete time intervals (frames) rather than continuous monitoring. The controller samples the sensor data at periodic intervals during sleep mode, analyzing motion patterns across these periodic samples to determine wake-up conditions. This periodic sampling maintains wake-up responsiveness for approaching users while significantly reducing power consumption compared to continuous monitoring, as the sensor and processor remain in low-power states between sampling intervals.
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 solution effectively reduces power consumption by ensuring the display only wakes up when a user is intentionally approaching, thereby extending battery life and maintaining the efficiency of sleep mode.
Implementation Method 1
detecting, by a controller based on data collected by a time of flight (ToF) sensor, a movable object within a field of view of the electronic device
Data Source
AI summary
A method for operating an electronic device includes while a display is in low power mode, detecting based on data collected by a time of flight (ToF) sensor, a movable object within a field of view of the electronic device; in response to the detecting initiating a period of detection having a plurality of frames, the period of detection being a time period over which a distance value indicative of a distance between the movable object and the display is detected; for each of the plurality of frames, changing the distance value to reflect whether the movable object is moving near or further from the electronic device; detecting that the distance value after the period of detection is less than a threshold distance value indicative of the movable object approaching the display; if the distance value is less than the threshold distance value, waking up the display.