Design Of Android Smartphone’s ECG And Respiratory Signal Monitoring System Based On Bluetooth

The cardiovascular disease with the characteristics of high morbidity and high mortality is serious threat to human health. ECG signal and respiration signal is an important physiological signals. Especially the ECG signal, with a strong regularity and carrying abundant physiological information, is the main basis for the diagnosis and the treatment of cardiovascular disease. The conventional electrocardiogram(ECG) machine used in medical places is expensive and most of the portable ECG monitoring products in the market have hindered its further development because of the disadvantages such as large volume, large power consumption, single function and so on. In view of the above problems, this paper designs a portable ECG and respiratory monitoring system based on Bluetooth technology and Android mobile phone and themonitor system can realize the whole nature, real time ECG and respiratory signal monitoring. The signal processing and display part is realized by the Android system and this design method has the advantages of low cost, small size, low power consumption, and the monitoring system function can be further extended.MSP430F149 main control chip and ADS1292 R signal acquisition front-end chip use serial synchronous(SPI) communication mode to achieve the signal acquisition, analog digital conversion and transmission.The ADS1292 R can realize the amplification of ECG and respiratory signals, the suppression of common mode interference, 24 bit high precision A/D conversion.The main control chip and HC-06 Bluetooth module realize the signal transmission by the serial asynchronous communication. Android mobile phone client obtains the ECG and respiratory data send by remote Bluetooth(HC-06) through monitoring the local Bluetooth. According to the characteristics of weak and vulnerable ECG signals, the anti interference ability of PCB board is significantly enhanced by using symmetrical wiring and packet processing.The IIR digital filter, FIR digital notch filter and FIR digital low pass filter are designed to effectively suppress the baseline drift, power frequency interference and high frequency interference through the Android mobile phones. The filtered ECG data is used by Android mobile client to real-time draw and display ECG waveform through the SurfaceView method.After digital filtering, the R wave peak position was identified by the differential threshold method to calculate the heart rate, and the respiratory rate was calculated by the zero crossing counting method. The filtered ECG data is used by Android mobile client to real-time draw and display ECG waveform through the SurfaceView method. The heart rate, respiratory rate and the electrode lead status information of the background calculation are presented to the information bar of the display interface.After testing, the monitoring system can collect and analyze ECG and respiratory signals well, and it is convenient for users to observe the ECG waveform, heart rate and respiratory rate to judge the health status of the body. The system has certain significance for the treatment of cardiovascular diseases.