便携式电子脉搏计的设计

Design of a portable electronic pulsometer

设计了一种基于压电传感器以AT89S51单片机为核心构成的简易便携式电子脉搏计。其设计思路是用压电传感器把待检测对象的脉搏跳动转变成电信号,但是由于信号比较微弱,需要经过放大整形后才可以得到规则的脉冲波形。放大电路采用三运放高共模抑制比放大电路,将传感器的微弱信号放大。放大后的信号采用一阶低通滤波电路进行整形除去杂散信号,然后经过单片机定时计数后通过译码电路就可以从数码管直接读出被测对象的脉搏数了。定时由基准时间产生电路完成,它是通过555集成电路构成一个单稳触发器来实现的。AT89S51单片机构成的控制电路在软件的作用下控制脉搏信号放大、整形和倍频后进入计数器的时间。该便携式电子脉搏计优点是制作简单,使用元器件少,工作稳定可靠,显示直观,误差不大于1%,成本低廉且能节电。

A kind of simple portable electronic pulsometer based on piezoelectric sensor is designed, which constituted with single-chip microcomputer AT89S51. The piezoelectric sensor is used to transform pulse beating into electrical signal. Because the signal is very weak, the regular pulse profile is only obtained after enlargement and reshaping. Three-operation-amplifier circuit is used to magnify the weak signal from sensor, and the one-order low-pass filter is used to reshape the signal to get rid of miscellaneous signals. After timing and counting by the single-chip microcomputer, the pulse number is directly shown on light-emitting diode tubes through decoding circuit. The norm time generation circuit, a single steady trigger consisted of 555 integrated circuit chip mainly, set the standard time. The single-chip microcomputer AT89S51 circuit control the enlargement and reshaping of the original signal and time trigger. This portable electronic pulsometer has many advantages, such as simple structure, steady and reliable working, direct number display, low error （〈 1%）, low cost, and electricity saving.