An ear-lead ECG based smart sensor system with voice biofeedback for daily activity monitoring

The computer-based portable devices lead our societies to the world of u-healthcare, so that people may monitor their heart rate outside hospitals. The paper proposes an ultra-wearable smart sensor system combines electrocardiogram (ear-lead ECG), tri-axial accelerometer, and GPS sensors to measure normal or elderly person’s daily activities. The ear-lead makes possible to measure ECG signals without any chest belt or sticky tape. It measures the ECG signals from an ear to an arm. According to our research, the ear-lead is linear combination with regular ECG lead I and III. For most of people, especially, the ear-lead is highly correlated with lead-I ECG. Lead I can be used to detect some life-threatening ECG signals with critical heart rate or morphology changes such as ventricular tachycardia (VT), ventricular flutter (VFL), or ventricular fibrillation (VFib). The hardware of smart sensor integrates a TI MSP430 microprocessor, Bluetooth wireless transmission to PC client software, micro SD card storage, and LCD display. The embedded algorithm combines two sensors for noise reduction and utilizes voice biofeedback for exercise overload warning.