Rhee S, Yang B H, Asada H H
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge 02139, USA.
IEEE Trans Biomed Eng. 2001 Jul;48(7):795-805. doi: 10.1109/10.930904.
A miniaturized, telemetric, photoplethysmograph (PPG) sensor for long-term, continuous monitoring is presented in this paper. The sensor, called a "ring sensor," is attached to a finger base for monitoring beat-to-beat pulsation, and the data is sent to a host computer via a radio-frequency transmitter. Two major design issues are addressed: one is to minimize motion artifact and the other is to minimize the consumption of battery power. An efficient double ring design is developed to lower the influence of external force, acceleration, and ambient light, and to hold the sensor gently and securely on the skin, so that the circulation at the finger may not be obstructed. Total power consumption is analyzed in relation to characteristics of individual components, sampling rate, and CPU clock speed. Optimal operating conditions are obtained for minimizing the power budget. A prototype ring sensor is designed and built based on the power budget analysis and the artifact-resistive attachment method. It is verified through experiments that the ring sensor is resistant to interfering forces and acceleration acting on the ring body. Benchmarking tests with FDA-approved PPG and electrocardiogram reveal that the ring sensor is comparable to those devices in detecting beat-to-beat pulsation despite disturbances.
本文介绍了一种用于长期连续监测的小型化遥测光电容积脉搏波传感器（PPG）。这种被称为“指环传感器”的传感器附着在手指根部以监测逐搏搏动，数据通过射频发射器发送到主机。解决了两个主要设计问题：一是将运动伪影降至最低，另一个是将电池功耗降至最低。开发了一种高效的双环设计，以降低外力、加速度和环境光的影响，并将传感器轻柔且稳固地固定在皮肤上，从而不会阻碍手指的血液循环。结合各个组件的特性、采样率和CPU时钟速度分析了总功耗。获得了使功耗预算最小化的最佳操作条件。基于功耗预算分析和抗伪影附着方法设计并制造了指环传感器原型。通过实验验证了指环传感器能够抵抗作用在环体上的干扰力和加速度。与FDA批准的PPG和心电图进行的基准测试表明，尽管存在干扰，指环传感器在检测逐搏搏动方面与那些设备相当。
