Plessey, available from Glyn High-Tech Distribution has developed a new sensor solution to monitor driver fatigue.
According to the British Royal Society for the Prevention of Accidents, driver fatigue may cause up to 20% of road accidents and up to a quarter of fatal and serious accidents. With safety considered a strong selling point, car manufacturers are constantly looking for ways to make their vehicles safer.
Until recently, measuring ECG in a car meant the driver having a set of electrodes attached to their bare chest using gel. Based on Plessey’s multi-award winning EPIC sensor technology, the new solution utilises capacitive coupling, eliminating any need for skin contact and measuring ECG through normal clothing and seat cover fabric.
By monitoring a parameter called Heart Rate Variability (HRV), which is 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’s sensor solution consists of 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 minimised 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 the driven ground to the steering wheel. The system has been shown to be completely immune to electrical noise sources within the car.
Plessey’s evaluation kits for car manufacturers and suppliers include a seat pad containing a 6-sensor array on the seat back and a ground plane on the base in addition to an interface box with a USB output to the display and recording software.