In this study a sorting scheme with remote monitoring and operating function for fruits by using photoelectric elements is established. The hardware for this prototype is composed of a photointerrupter, measurement platforms, a data acquisition card, and a personal computer. The friendly human-machine interface software is a LabView program by which dominates the sorting algorithm, data flow and recording, and the parameter setting. The photointerrupter structure consists of a Wheatstone bridge and are lay along with other electronic components. One of the four resistors in the bridge is replaced by a photoresistor as the element of the measurement platforms.udThere are 48 Wheatstone Bridges were used and are divided into six groups in this study, Only three groups work for each direction scanning. The photoresistors are assembled in matrix on the measurement platform. The measurement platform is equipped with two light sources for vertical and lateral views respectively. The shadows of fruits tested on platform are recognized as their sizes from the photo resistances in photoresistors matrix. The signals equivalent to the photoresistance were captured into the computer by a DAQ interface (PCI-6024E). Then, a LabView program outfitted the sorting algorithm executes the sorting task. The sorting results will be exhibited both on monitor and by voice announcement simultaneously. Far-distance operation is also available on Internet. The on-line system performance shows that there are average long-axis error in 3.94%, average length error in 3.93% and average width-margin error in 3.31% for Fuji apples and average stalk height error in 3.06%, average longitude axis error in 4.13%, average width-margin error in 3.02% for peaches. The overall error will be within 5%. These validate this accomplished system.
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