Sorting machine using dual frequency optical detectors

摘要

A photo-optical detector for use in a multi-chromatic sorting machine, including at least two separate photodiode materials (50, 51) responsive to different frequency bands and a filter having transmission response characteristics that are defined in a frequency range including the said frequency bands of the materials. The sorting machine using such detectors can be selectively programmed using the various resulting signals from the detectors after appropriate amplification and threshold detection to cause resulting ejection mechanism activation.