German sensor manufacturer Hoffmann + Krippner has developed and patented some interesting technology to address the issue of drivers losing concentration die to fatigue New SensoInk and SensoFoil (.pdf) potentiometer technology enables a resistive sensor to be printed for measuring pressure, sensitivity, and position of the driver's hands on the steering wheel.

SensoFoil membrane potentiometers are used as voltage dividers and consist of several layers, which are separated by a spacer. The layers are connected to each other through mechanical or magnetic pressure, the pressure sensitive ink creating resistance between the thin layers of plastic.

It’s easy to imaginre how the SensoFoil can be retrofitted to car steering wheels to detect how tightly the wheel is being gripped, in order to identify when a driver’s concentration is slipping. Drivers grip the wheel or move their hands across it all the time, and the system detects an absence of such movements, which could suggest the driver has fallen asleep or become ill. In response to such changes an alert is triggered to restore concentration or prompt the driver to take a rest. Guttersberg Consulting owns the international manufacturing, marketing and licensing rights to the hands-on detection system.