Diffraction-based small wire detection

This paper proposes a method of small wire detection based on diffraction. The light beam is generated by a laser head with its focus on the central of a photosensitive element, and an electronic detection and switching module is developed to detect whether a wire or the like supplied to an operation machine is present. In response to a small wire or the like sitting in the laser beam, a diffraction pattern will be projected to the photosensitive element. As a result, output signal to the actuator is generated for proper action. Upon removal of the small wire or the like due to inadvertent breakage or misfeeding, received signal will change accordingly. Industrial experiment has demonstrated the effectiveness of the proposed detection method.