DESIGN AND MANUFACTURING OF PROTOTYPE FOR ORANGE GRADING USING PHOTOTRANSISTOR

Abstract

Fruits are usually graded according to their quality. The purpose of the grading is to grad fruit into uniform categories (according to size, shape, weight, color and ripening stage). So the fruit can be classified as different grades according to the requirements of the market. Due to the lack of the small grading machinery to fit small farms and higher prices of large grading machinery,  therefore this study aimed to designing,  manufacturing and performance evaluating of a prototype for orange grading based on the dimensions of the fruit, which take place without physical contact. The prototype uses different successively operating components, such as phototransistors and actuators, each performing a specific task. The operating principle depend on the phototransistor, signal gathering circuit are also provided, a processing circuit and output circuit for distributing unit. When it works, the system receives digital signals produced by fruits that shadow the light from a phototransistor sensor during fruit measuring. After digital signals processed by the electronic circuit, every fruit’s sizing level is deduced. Then, the system will output switch signals to open the sorting switches according to fruits’ size.

Testing of the grading prototype was statistically factorial in completely randomized design, featuring three control factors (conveyor chain velocity, sphericity percentage of fruit and stopping time) and three performance evaluation parameters (grading efficiency, damage percentage and productivity. The result showed that the best degree of grading efficiency obtained with the best degree of damage percentage were at 0.15m/s chain velocity and 1.5 sec Stopping time.