Apparatus for determining the drowsiness and method therefor

A device for determining the drowsiness has a pulse wave or -schlagsensor (10) and a determination circuit (20). The sensor (10) is provided on a steering wheel (1) to detect a pulse wave or a pulse of a driver who holds includes the steering wheel (1). The determination circuit (20) generates a thorax pressure signal indicative of the depth of breathing by envelope detection of a pulse wave signal of the sensor (10) and mitttels a comparison of the pattern of the thorax pressure signal establishes a reference pattern, whether the driver is drowsy , The display (30) and the buzzer (40) Report to the driver and any other occupants each driver's drowsiness by means of a visual display and a buzzing sound. A movement of the body surface can be used as a signal that is indicative of the depth of breathing.