“Asleep at the wheel” is a dangerous situation for the driver, passengers, and occupants of other vehicles on the road or even bystanders. A heart attack or other cardiovascular emergency can also result in sudden incapacitation that can have deadly consequences. As a result, vehicle manufacturers are working to develop systems that will automatically detect when a driver is unable to control the car or truck adequately, and then trigger an emergency stop system that will bring the vehicle safely to a stop.
Researchers at the Fraunhofer Institute for Photonic Microsystems (IPMS) are working on a key component of such a system. They have developed a way to measure electrocardiogram (ECG) signals without making contact with the driver’s skin. The sensors rely on capacitance, using large metal plates embedded in the driver’s seat. These plates are able to detect the electrical charges associated with the heartbeats even through several layers of clothing. This passive approach means that the driver does not have to wear a separate device, or deal with possible skin irritation that can occur when wearing contact electrodes for long periods of time.
The signals received by the device are very faint, so the sensors must be shielded from other sources of electrical activity. The system also must be able to detect the signals accurately even when the driver moves in the seat. The researchers see other potential applications for this technology, such as embedding the sensor plates in clothing for better accuracy, or placing the electrodes in hospital beds to monitor a patient’s heartbeat without the need for contact electrodes.