Abstract: The invention contemplates an improved air flow sensor including a proximity switch which has a metal disk mounted with respect to the sensing face to be movable by air flow in the action zone of the magnetic field as between a position adjacent the sensing face to a position away from the face or visa versa whereby the switch oscillator is off and on respectively at the two extremes to provide an indication of the condition. The air flow sensor is shown herein in apparatus to calculate breathing rate, in object detection apparatus, and in vacuum lift apparatus.