| abstract |
A driver inattention detection system includes a rotary encoder (e.g., an optical rotary encoder) operably associated with a steering column of a vehicle and configured to produce steering signals representing the magnitude and direction of rotation of the steering column. A drive wheel concentrically coupled to the rotatable shaft of the encoder has a knurled peripheral edge that frictionally engages the steering column or a frictional band surrounding a portion of the steering column. A control module determines a steering count and if a driver inattention condition exists. The driver inattention condition exists if the vehicle is traveling above a minimum speed, and there has been no recent braking activity, and the active steering count is below a determined minimum threshold steering count. Separate first and second alarm modules operably coupled to the control module may be independently activated in a progressive manner. All sensed conditions and responses may be logged. The encoder may be calibrated to accurately indicate steering action. The system may be calibrated to determine an appropriate minimum steering count for a determined time period for the particular vehicle. Cruise control is disabled if a driver inattention condition persists after alarm activation. |