Body bio-impedance is a unique parameter to monitor changes in body composition non-invasively. Continuous measurement of bio-impedance can track changes in body fluid content and cell mass and has widespread applications for physiological monitoring. State-of-the-art implementation of bio-impedance sensor devices is still limited for continuous use, in part, due to artefacts arising at the skin-electrode (SE) interface. Artefacts at the SE interface may arise due to various factors such as motion, applied pressure on the electrode surface, changes in ambient conditions or gradual drying of electrodes. This paper presents a novel bio-impedance sensor node that includes an artefact aware method for bio-impedance measurement. The sensor node enables autonomous and continuous measurement of bio-impedance and SE contact impedance at ten frequencies between 10 kHz to 100 kHz to detect artefacts at the SE interface. Experimental evaluation with SE contact impedance models using passive 2R1C electronic circuits and also with non-invasive in vivo measurements of SE contact impedance demonstrated high accuracy (with maximum error less than 1.5%) and precision of 0.6 Ω. The ability to detect artefacts caused by motion, vertically applied pressure and skin temperature changes was analysed in proof of concept experiments. Low power sensor node design achieved with 50mW in active mode and only 143 μW in sleep mode estimated a battery life of 90 days with a 250 mAh battery and duty-cycling impedance measurements every 60 seconds. Our method for artefact aware bio-impedance sensing is a step towards autonomous and unobtrusive continuous bio-impedance measurement for health monitoring at-home or in clinical environments.

中文翻译：

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用于连续生物阻抗监测的无线、人工制品感知阻抗传感器节点。

身体生物阻抗是一种独特的参数，可以无创监测身体成分的变化。生物阻抗的连续测量可以跟踪体液含量和细胞质量的变化，并在生理监测方面具有广泛的应用。最先进的生物阻抗传感器设备的实现仍然受限于连续使用，部分原因是皮肤电极 (SE) 界面处出现的人工制品。由于各种因素，例如运动、电极表面上施加的压力、环境条件的变化或电极的逐渐干燥，SE 界面处的伪影可能会出现。本文提出了一种新型生物阻抗传感器节点，其中包括一种用于生物阻抗测量的人工制品感知方法。传感器节点能够在 10 kHz 至 100 kHz 之间的十个频率下自主和连续测量生物阻抗和 SE 接触阻抗，以检测 SE 界面处的人工制品。使用无源 2R1C 电子电路对 SE 接触阻抗模型进行的实验评估以及 SE 接触阻抗的非侵入性体内测量显示出高精度（最大误差小于 1.5%）和 0.6 Ω 的精度。检测能力在概念实验证明中分析了由运动、垂直施加的压力和皮肤温度变化引起的人工制品。低功耗传感器节点设计在活动模式下为 50mW，在睡眠模式下仅为 143 μW，估计电池寿命为 90 天，使用 250 mAh 电池和每 60 秒进行一次占空比阻抗测量。我们的人工制品感知生物阻抗传感方法是朝着自主和不显眼的连续生物阻抗测量迈出的一步，用于在家中或临床环境中进行健康监测。