Design Of Multi-functional Portable ECG Monitor Based On Cortex-M3

Electrocardiogram (ECG) is an important method for diagnosis of cardiovascular diseases (CVD). Typically, clinical ECG monitors are categorized into routine ECG (RECG) monitors and dynamic monitors (Holter) according to the signals’sampling accuracy and recording duration. Since CVD is sudden, transient and dangerous, it is necessary to develop an ECG equipment integrated with both functions of RECG and Holter, which not only meets the requirement of low cost and portability in community hospitals, but also has important clinical implications for the early prevention and diagnosis of CVD.Unlike RECG that involves a static and short-term but high-precision recording, Holter requires continuous24-hour recording that produces a large capacity of data. This paper designed a Cortex-M3-based multi-functional portable ECG monitoring system for both continuous24-hour dynamic ECG recording and instant routine ECG examination in case of emergency. The ECG monitoring system utilized LPC1788based on the core of ARM Cortex-M3as the control unit, which has a fast computing power and peripheral resources such as the USB interface, SD card interface. The system also utilized the chip of ADS1298from Texas Instruments as the analog front-end of ECG, and added such peripheral circuits as pre-processing modules and the right-leg driver, thus developing a low-power and low-noise ECG acquisition module. By SD card technology and embedded FAT16file system, the system completed a large-capacity data storage, and the use of USB2.0technology has achieved high-speed data transmissions.The testing result of the prototype has shown that the operating current of the entire system was50.1mA, which indicated that the device can work continually for more than24hours with the power supply of two AA batteries. On the other hand, the system implemented a large-capacity data storage and high-speed data transmission, and thus achieved the switch of dynamic ECG monitoring and routine ECG examination. The portable device is low cost, low power, and multi-function to meet the demands of both community hospitals and home healthcare for the ECG monitoring.