Wearable Device Power Saving via Sensor Buffer Threshold
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Solution Overview
Problem
Wearable devices consume power quickly due to the need to continuously collect and process large amounts of sensor data, reducing their usage time.
Innovation Solution
Implementing a hibernate mode for processing units in wearable devices, where units are only woken up when necessary to receive or transmit data, with sensors accumulating data in a buffer until a threshold is reached before processing, and units returning to hibernate mode after data processing is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the processing unit continuously collects and processes sensor data, then the functionality and measurement precision are improved, but the power consumption increases and usage time decreases
Solution Approach 1:
The processing unit operates in periodic cycles, alternating between active sensing states and hibernate states. The sensor accumulates sense data in a buffer during active periods, then the processing unit enters hibernate mode until the buffer reaches a threshold, at which point it is woken up to process the accumulated data. This periodic operation pattern significantly reduces average power consumption while maintaining continuous sensing capability.
Solution Approach 2:
The sensor continuously accumulates sense data in the buffer before the processing unit needs to process it. This preliminary data accumulation allows the processing unit to remain in low-power hibernate mode longer, waking up only when the buffer threshold is reached, thereby reducing the frequency and duration of high-power active states.
2Productivity
If the processing unit processes sensor data continuously, then the productivity and responsiveness are improved, but the duration of action decreases due to rapid power consumption
Solution Approach 1:
The system implements periodic processing cycles where the processing unit alternates between active processing and hibernate states. During active periods, it processes accumulated data from the buffer; during hibernate periods, it consumes minimal power. This periodic pattern extends the duration of action (usage time) while maintaining productivity through batch processing of accumulated data.
Solution Approach 2:
The sensor buffer acts as a copy mechanism, storing accumulated sense data in a buffer memory before the processing unit retrieves and processes it. This allows the processing unit to work with copied data from the buffer rather than continuously accessing the sensor, enabling more efficient batch processing and longer hibernate periods.
3Use of energy by moving object
If the processing unit enters hibernate mode to save power, then the power consumption is reduced, but the response time and productivity decrease
Solution Approach 1:
The sensor continuously accumulates data in the buffer before the processing unit needs it, performing preliminary data collection during low-power periods. When the processing unit wakes from hibernate mode, the data is already ready in the buffer, minimizing the actual processing time and reducing the effective response time loss despite the hibernate period.
Solution Approach 2:
The system uses a buffer threshold mechanism as feedback control. When the accumulated data in the buffer reaches a predetermined threshold, this triggers the processing unit to wake from hibernate mode. This feedback-based triggering optimizes the balance between power saving and response time by waking up only when sufficient data has accumulated, avoiding unnecessary wake-ups while ensuring timely processing when data is available.
Data Source
AI summary
A wearable device and a power saving method are proposed. The wearable device includes a sensor and a first processing unit. The sensor has a buffer. The first processing unit is coupled to the sensor. The first processing unit in a first hibernate mode is woken up after receiving a first signal, wherein the first processing unit includes an interrupting module. The interrupting module makes the first processing unit enter the first hibernate mode after commands, in response to the first signal, the sensor to start sensing so as to generate sense data, wherein the sensor wakes up the first processing unit from the first hibernate mode based on an amount of the sense data exceeding a threshold of the buffer, and the first processing unit enters the first hibernate mode after processing the sense data.