Digital blood pressure monitor

Abstract

In this work we present a blood pressure monitor which measures both the high blood pressure (systolic pressure), and the low blood pressure (diastolic pressure). It is a semiautomatic meter because the inflation of the occlusive cuff is carried out in a manual way. The transducer used is a piezoresistive silicon pressure sensor integrated on chip which provides a proportional voltage to the input pressure, with a measurement range from 0 to 50 kPa (0– 7.3 PSI). The oscillometric method is employed, which consists on detecting the oscillometric signal on brachial artery, being processed at each pressure step, when the cuff is gradually deflated. Signal sampling is carried out at a rate determined by the heart rate. In order to program the digital electronics of the circuit we used Altera tools, with the compiler MAX-PLUS II, and the device selected to implement the design was an EPM7128SLC84-15 CPLD (Complex Programmable Logic Device)