Preh Automotive Human-Machine Interface (HMI) (http://rbi.ims.ca/4911-545). To reduce the number of driver controls for vehicle interior functions, Preh engineers designed a flexible human-machine interface (HMI) consisting of a control knob, programmable buttons, and a touch pad display. Pushing, rotating, and tilting the centrally-located knob selects specific functions, such as air conditioning or seat position. Once the buttons' functions are assigned based on the driver or passenger's selection, a colored LED illuminates the appropriate icon. The touch pad provides input for the navigation system. The LEDs and LED driver IC for the HMI are selected based on the car manufacturers' requirements, which vary from bright for daylight visibility to a more subdued level.