Development of a wearable health monitoring device with motion artifact reduced algorithm (ICCAS 2007)

In this paper, a real-time, wearable and motion artifact reduced health monitoring device is represented. A finger band, wearable health monitoring device, is consists of photoplethysmography (PPG) sensor, 3-axis accelerometer, microprocessor and wireless module. The PPG sensor acquire distorted heart beat signal due to motion artifact. The finger movements are detected using the accelerometer, and major motion directions causing of the noise are researched by comparing each directional motion signals and distorted PPG signal. Two directional motions are significantly related to noise, therefore, these two directional active noise cancellation algorithm was applied to reconstruct the noise added heart beat signal. Low order (4th order) NLMS (normalized Least Mean Square) adaptive filter is employed for small size wearable device. The finger band device is experimented in daily body motion condition (1–3 Hz), and reduce distortion rate less than 5% by active noise cancellation algorithm. The motion artifact reduced finger band sensor can offer continuous health monitoring without daily motion artifact.