Design Of Fetal ECG Monitoring System Based On Smart Phone

Non invasive fetal ECG monitoring can detect fetal distress,congenital heart disease,umbilical cord entanglement and other pathological conditions,and then take effective treatment for the fetus.At the same time,the FECG signals in the abdominal ECG signals are very weak,and the FECG signals are interfered by noises such as maternal ECG.The existing fetal ECG extraction algorithms and monitoring systems are mostly non real-time.It is first to use the equipment to collect and store pregnant women's abdominal and chest electrocardiogram signals,and then extracts the fetal ECG based on the PC machine.This paper proposes a new fetal ECG monitoring system based on smart phone.The fetal electrocardiogram collector collects the 3 leads pregnant abdominal ECG signals,and sends the ECG signals to the smart phone through bluetooth.The smart phone APP software is designed,and it filters abdominal ECG signals by IIR,and uses real-time Fast independent component analysis(ICA)algorithm to extract fetal ECG.The fetal ECG and heart rate are displayed in real-time on the mobile phone interface,and abnormal heart rate is warned.This paper describes the hardware,software and algorithm design of fetal ECG monitoring system based on smart phone in detail,and tests the performance of each part.The main contents of this paper are as follows:1.Design of fetal ECG collector.The bluetooth processor CY8C4247 is the main processor,and the 3 lead analog front-end integrated chip ADS1293 is used to collect abdominal ECG,the circuit is powered by lithium ion battery.The battery is charged by the Type-C interface through the charging chip MCP73831,and the TLV70033 3.3V voltage regulator chip supplies power to each module.It is made by printed circuit board(PCB),the embedded driver is debugged,the shell is designed,and the prototype is made.2.Design of fetal ECG signal generator.The MSP430F149 is main processor and the eight digit mode conversion chip DAC5571 s output the three leads ECG signals of the abdomen and the single lead fetal ECG signal stored in the processor Flash.The circuit is powered by 5V USB line,and the LM117-3.3V voltage regulator chip supplies power to each module.Touch key is used to regulate the amplitude and heart rate of fetal electrocardiogram and the results are displayed on 0.96 organic light emitting diode(OLED)screen.It is made by PCB.The embedded driver is debugged,the shell is designed,and the prototype is made.3.Android smart phone fetal ECG extraction APP design.It includes interface design,bluetooth low energy(BLE)connection service,real-time extraction algorithm transplant,fetal history ECG storage and playback view,abnormal fetal ECG and disease analysis,user registered login design and so on,the fast ICA algorithm is used to extract and display the fetal ECG at the cell phone end in real-time.After the system performance test,the work of fetal ECG collector can be over 24 hours.The random 30 minutes real-time extracted fetal ECG signals are tested,the experimental results show that the accuracy is 94.79% and the sensitivity is 99.21%.This system has realized the basic function of fetal ECG home monitoring,and has high market value.