Design of Seat Mounted ECG Sensor for Detecting Absent-Mindedness in Vehicle

The causes of deaths in traffic accidents are predominantly human factors such as carelessness or absent-mindedness while driving. A non-contact electrocardiography (ECG) monitor for continuous detection while driving is needed to reduce the number of fatal accidents by human error. The authors have designed an effective circuit configuration for common noise resistance, considering the effect of a sitting posture according to source impedance of intermediary materials such as clothing and seat cover. The sensor system employed a DRL (driven-right-leg) circuit with source impedance monitor, and was composed of at least two sensor heads mounted into the seat cover and an electrode mounted on the steering wheel to reduce common-mode noise in cardiac electricity frequency. The authors succeeded in attaining stable detection of cardiac electrical impulses during driving, stable driving at an average speed from 60 to 100 km/h, operation of the accelerator, brake, steering wheel, and direction indicators. In addition, they tried estimating the driver’s absent-mindedness by ECG over a long time period measured by medical equipment when driving. From the this trial’s results, RRI analysis indicates that they can detect the driver’s absent-mindedness using ECG signals.