Plessey developed sensor monitors driver fatigue

Date
10/29/2012

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Monitoring HRV (Heart Rate Variability) measures driver fatigue

Epic sensor monitors driver alertness

Plessey is using its EPIC sensor technology to monitor driver fatigue. According to the British Royal Society for the Prevention of Accidents, research shows driver fatigue may be a contributory factor in up to 20% of road accidents and up to a 25% of fatal and serious accidents. Car manufacturers are constantly looking for ways to make their vehicles safer, especially as safety can be a strong selling point. Until recently, measuring ECG in a car meant the driver having a set of electrodes attached to the bare chest using gel. However, because the EPIC sensor utilises capacitive coupling, it doesn't rely on good skin contact, and can actually measure ECG through normal clothing and seat cover fabric. Monitoring the HRV parameter - a measure of how stable the heart rate is from beat to beat - it is possible to tell when the driver is starting to become sleepy. Plessey recommend an array of sensors built into the seat back, so that the optimal sensing location can be chosen, regardless of the driver's height and build. Movement noise is minimized by placing the sensors away from the shoulders on the lower part of the seat back. The system uses a capacitive driven ground plane, which can also be placed under the seat cover fabric on the base of the seat, to produce a completely hidden system. Further noise reduction can be achieved by coupling this driven ground to the steering wheel. The system has been shown to be completely immune to electrical noise sources within the car. Plessey now has available evaluation kits for car manufacturers and suppliers. This takes the form of a seat pad containing a 6 sensor array on the seat back and a ground plane on the base. The demonstration kit also includes an interface box with a USB output to the display and recording software. Plessey's own tests show that more than 95% of heart beat peaks were detected during a ten minute trial over a variety of driving conditions. ? EPIC sensor datasheets EPIC application notes EPIC video Plessey Semiconductors

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