Sewing machine with a cloth-edge detector

摘要

A sewing machine with a cloth-edge detector has a light source for casting light on a sensing point on a cloth, and a light receiver for generating an intensity signal according to the intensity of the received light. Before sewing, a reference signal is set at an average of two intensity signals that are gauged before and after a cloth edge. The cloth edge can be detected by comparing the intensity signal from the light receiver with the reference signal.