Another pet project of mine is the plastic detector. I was asked by a friend Howard Walker, who owns a dump, to build one.
I tried many things. Then I ran light through two opposed polarizes. Plastic between the polarizes depolarizes the light. The bottles and plastic containers light up like a Christmas tree when viewed though the viewer. I am now adding a prism on the far end of the apparatus. I may be able, with this arrangement, to separate plastics by type. I've found that pet Pepsi bottles do not pass IR while cloudy milk bottles do. I am not sure of the spectral range of the various polarizing materials. Modulating the light beam keeps ambient light from interfering with the detection process. Another project is the singing bird house. It sings like a bird when the sun hits it. I would like to try this one at craft shows. My feeonsee is a go on this one. Frank Z
