Electric field sensor monitors driver fatigue
The PS25203 features a lower gain and higher input impedance making it ideal for certain types of contactless ECG measurement such as driver fatigue monitoring or seat occupancy. The EPIC sensor works by measuring tiny changes in an electric field in a similar way to a magnetometer detecting changes in a magnetic field even at a distance and through clothing.
There are several applications where EPIC can be used in cars. For example, driver monitoring for health and alertness by detecting heart rate and respiration or determining the occupancy of the car to adjust the ride, handling and air bag deployment depending on the size and location of occupants. The EPIC sensor electrodes can be easily and discretely incorporated inside the seat backs to acquire the necessary biometric data. The sensor can be integrated on a chip with other features such as data converters, digital signal processing and wireless communications capability.
The technology works at normal room temperatures and functions as an ultra-high, input impedance sensor that acts as a highly stable, extremely sensitive, contactless digital voltmeter to measure tiny changes in the electric field down to milliVolts. Most places on Earth have a vertical electric field of about 100 Volts per metre. The human body is mostly water and this interacts with the electric field. EPIC technology is so sensitive that it can detect these changes at a distance and even through a solid wall.
EPIC sensors are already in commercial production by Plessey. By adjusting the DSP and amplification circuitry, the sensors can be tuned for detection at a distance as required for these automotive applications. Volume production pricing for the PS25203 is in the region of $1-2. The PS25203 is supplied in a custom 4-pin PCB hybrid package measuring 10.5mm x 10.5mm x 3.45mm.
Application notes are available at www.plesseysemiconductors.com/products/epic/applications/
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