tailieunhanh - a single-chip pulsoximeter diesgn using the msp430

Báo cáo ứng dụng thảo luận về những thiết kế của plethysmography quang học không xâm lấn còn gọi là pulsoximeter sử dụng MSP430FG437 vi điều khiển (MCU). Pulsoximeter Các bao gồm một thiết bị ngoại vi thăm dò kết hợp với MCU hiển thị độ bão hòa oxy và nhịp tim trên một ly LCD. cùng cảm biến được sử dụng để phát hiện tim suất và pulsoximetering trong ứng dụng này. Thăm dò sẽ được đặt trên một điểm ngoại vi của cơ thể chẳng hạn như một đầu ngón tay, thùy tai hoặc mũi. Thăm dò bao gồm hai ánh sáng ôt. | Application Report SLAA274A-November 2005-Revised June 2010 A Single-Chip Pulsoximeter Design Using the MSP430 Vincent Chan Steve Unde ÕQơỊIIỄỄỄỄIIỄỄỄỄIIỄỄỄỄIIỄỄỄỄIIỄỄỄỄIIỄỄỄỄIIỄỄỄỄIIỄỄỄirMSP430 Products ABSTRACT This application report discusses the design of non-invasive optical plethysmography also called as pulsoximeter using the MSP430FG437 microcontroller MCU . The pulsoximeter consists of a peripheral probe combined with the MCU displaying the oxygen saturation and pulse rate on a LCD glass. The same sensor is used for both heart-rate detection and pulsoximetering in this application. The probe is placed on a peripheral point of the body such as a finger tip ear lobe or the nose. The probe includes two light emitting diodes LEDs one in the visible red spectrum 660 nm and the other in the infrared spectrum 940 nm . The percentage of oxygen in the body is worked by measuring the intensity from each frequency of light after it transmits through the body and then calculating the ratio between these two intensities. A revised version of this application is described in the application report Revised Pulsoximeter Design Using the MSP430 SLAA458 . 1 Introduction The Pulsoximeter is a medical instrument for monitoring the blood oxygenation of a patient. By measuring the oxygen level and heart rate the instrument can sound an alarm if these drop below a pre-determined level. This type of monitoring is especially useful for new born infants and during surgery. This application report demonstrates the implementation of a single chip portable pulsoximeter using the ultra low power capability of the MSP430. Because of the high level of analog integration the external components can be kept to a minimum. Furthermore by keeping ON time to a minimum and power cycling the two light sources power consumption is reduced. 2 Theory of Operation In a pulsoximeter the calculation of the level of oxygenation of blood SaO2 is based on measuring the intensity of light that has been .