I am working with my friend Howard Walker. He is in the junk plastic business. The plastic bottles are worth 12 cents a pound in bulk. If separated into 1,2,3,4 and 5 the plastic is worth 24 cents a pound.
I found that #1 the clear coke bottle plastic if opaque to mid infrared. I blocks a security lights thermal sensor. It transmits visible light. This was a good find as these bottles are worth the most separated. A ratio detector should work well. I found #2 milk bottle plastic is opaque to a blue LED light. The mid infrared goes right through it. A ratio detector should work well. I have found no detection method for #5 semi clear plastic. All light goes through it. Darn! It does, however, scatter a red laser. I am not sure it this effect can be employed. They are all transparent to a UV black light. I did not expect this! The bottles are all smashed up and the detection technique must be robust. We will use a transmission test to avoid the labels. No transmission because of a label is not a condition. They are all transparent to near IR when I check it with my video camera and a TV remote. Too bad. any ideas? Frank Znidarsic
