Development Of A Portable Low-power Electrocardiograph Based On Raspberry PI

Electrocardiographs,ECG monitors,etc.are medical devices used to monitor ECG signals.As an important basis for doctors to discriminate heart disease,their accuracy is essential.Strict measurement verification is required to ensure the accuracy of the results..At present,the calibration instruments used for such devices in the market tend to be bulky,and the operation steps are cumbersome,which brings inconvenience to the on-site verification work of the verification personnel.In view of the above phenomena,this paper deeply analyzes the relevant national metrological verification procedures,the characteristics of various types of ECG monitoring medical equipment and the on-site operation procedures of the verification personnel,and summarizes the design requirements of the calibration instrument,which is small in size,easy to carry,and low in power.Based on the principle of convenient consumption and operation,a design scheme of an electrocardiograph calibration instrument based on RPI processor is proposed.The calibrator can generate square wave signals,sine wave signals,heart rate(HR)signals,differential signals,and ECG signals with amplitudes of millivolts or microvolts and frequencies of 0.1 to 100 Hz.Firstly,this paper introduces the principle of waveform signal generation,the basis of DAC selection and the principle of attenuation circuit.The overall design scheme of the calibration instrument is proposed,and the system portability and low power consumption design are realized.Then,the software and hardware system of the verifier is designed,and the Raspberry Pi is used as the main control processor.The operation interface of the calibration instrument is designed and developed by using the Qt library and the Visual Studio IDE.The interface operation is more convenient and friendly;the waveform function and the DAC are selected.Waveform signal,establish a function model of various waveforms,calculate the binary code of the signal output waveform data in real time through software,and generate waveform signal after DA conversion;adopt ?-type attenuation network,the signal voltage can be attenuated to millivolts or microvolts by selecting the attenuation circuit.Finally,the function test of the tester is carried out,and the source of the error of the output signal is analyzed and calculated in principle,and the theoretical error result is given.