Development of a Robot System for Sorting Polymer-Based Recycling

An Arduino-based automatic color sorting machine prototype has been designed and developed to classify PET bottles with different colors. Four color categories can be sorted by the prototype: fully transparent, green, blue, and other. The color identification is based on an RGB sensor and an ultrasonic sensor. The bottles are transported by a conveyor belt, and a pneumatic system is applied for bottle sorting. The color identification accuracy of the system reaches about 94%, and the sorting efficiency of the robot is about 20 bottles per minute. This robot may replace some manual sorting workers in the recycling industries to increase efficiency and reduce costs.