Fewer buttons, less effort, more control.

Preh Automotive [www.preh.com] has developed a human-machine interface [HMI] for luxury cars. Like BMW's iDrive and Audi's MMI, the Preh unit has a central control knob that can be rotated, pushed and tilted, though its range of motion is determined by the control strategy for each function. By restricting the operational paths, Preh engineers believe driver distraction will be reduced since navigation through menus will take less time and effort.

Blank buttons arrayed above the central controller are programmed to respond to the main function chosen. In this way, the same buttons can be used to control functions for the radio, seats, HVAC, etc. Pictograms of the various functions are projected onto the underside of the button via three colored LEDs, and feedback during button activation is similar to that of a traditional switch. The pictogram's pixel edge length is 0.18 mm, which Preh says gives an image resolution comparable to that found on a cellular phone or PDA display.

In addition to the reconfigurable switches and control knob, Preh added a touch pad like that found on a laptop computer. Rather than use the control knob to input information into the navigation system, users point and tap instead of turn and push. The claim is that it is easier to drag a cursor across a map or menu, and tap when the desired icon or area is reached.

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