Pulse Wave Sensor Sampling Rate Adjustment for Power Efficiency
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Solution Overview
Problem
Small-sized medical devices for measuring health indices like heart rate and stress face challenges in accurately measuring these parameters while minimizing power consumption due to their reliance on small batteries.
Innovation Solution
An apparatus and method that adjust the sampling rate of a pulse wave sensor based on a health index to be measured, using a sampling profile to identify different intervals for varying sampling rates, allowing for efficient data collection and processing of pulse wave signals, which can include heart rate, blood vessel stiffness, and blood pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pulse wave sensor operates at a high sampling rate to accurately measure health indices, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The sampling rate is dynamically adjusted based on the detected heartbeat state. During heartbeat intervals (when measurement accuracy is critical), the sampling rate is set to a first sampling rate. During non-heartbeat intervals, the sampling rate is reduced to a second sampling rate that is lower than the first sampling rate but not less than a reference sampling rate. This dynamic adjustment resolves the contradiction by matching sampling intensity to actual measurement needs.
Solution Approach 2:
The patent changes the sampling rate parameter according to the detected health index and heartbeat state. By identifying heartbeat intervals through analysis of pulse wave signals and adjusting the sampling rate accordingly, the system optimizes the balance between measurement precision and power consumption. The sampling rate is modified as a controllable parameter to adapt to different physiological states.
2Volume of moving object
If a small battery is used in a wearable device to maintain small size, then device portability is improved, but measurement reliability deteriorates due to limited power
Solution Approach 1:
The system dynamically adjusts the sampling rate based on heartbeat detection to maintain measurement reliability while conserving battery power. During heartbeat intervals when measurement reliability is most critical, the sampling rate is increased to the first sampling rate. During other periods, it reduces to the second sampling rate. This ensures that the limited battery capacity supports reliable measurements when needed most.
Solution Approach 2:
The patent implements periodic adjustment of the sampling rate synchronized with the heartbeat cycle. The processor identifies heartbeat intervals periodically and adjusts the sampling rate accordingly - using the first sampling rate during heartbeat intervals and the second sampling rate during non-heartbeat intervals. This periodic action pattern ensures measurement reliability is maintained during critical phases while conserving energy during less critical phases.
Data Source
AI summary
An apparatus for measuring a bio-signal includes a pulse wave sensor that may measure a pulse wave signal, of an object of interest, that is non-equidistantly sampled based on a sampling rate of the pulse wave sensor, and a processor that may identify, using a sampling profile, a first interval based on a health index to be measured. The processor may identify, using the sampling profile, a second interval based on the health index to be measured. The processor may set the sampling rate of the pulse wave sensor to a first sampling rate in the first interval. The processor may set the sampling rate of the pulse wave sensor to a second sampling rate, that is less than the first sampling rate, in the second interval.