Line laser-based break sensor that detects light spots on yarns

In this paper, current yarn break sensor systems are investigated and a line laser-based yarn break sensor is proposed. In this proposed sensor system, yarns aligned in the same plane are illuminated with a line light and the light spots on the yarns are detected with a CCD camera, total yarn number is compared with the number of the light spots formed by the line laser on yarns. If the number of the yarns used is greater than the number of the light spots, sensor warns the breaking.Design principles of the line laser-based yarn break sensor are presented. Detection area of the sensor related to the yarn number, yarn thickness and the distances between the yarns is obtained. Equations for calculating the line laser radiation angle and the light spot intensity related to the detection area width and the line laser placement height are obtained.Different placement situations of line laser (transmitter) and the CCD camera (receiver) related to the yarn plane are explained. An experimental setup is developed to test the system and the image of the light spots formed on yarns is obtained. Block diagram of the sensor is given and the operation principle is explained.