electric servos and electric controls for machines, namely on-off, position, and motor speed controls; automatic electro-optical sensors, namely spot, line scan, and area scan (array) sensors, for the detection of printed, etched, or machined features on materials, and memory controls for the feeding and positioning of materials; automatic electro-optical sensors for the detection, measurement, counting and indication of sheets of material present in a stack; automatic electro-optical sensors and control units for use with the foregoing