Thank you Jones. I want to detect the bottles before they are shredded and washed. All of the intact bottles float. They arrive dirty, crushed flat, and with the labels on and off.
Large recyclers have methods to do this. These methods are expensive at $100,000. There are a lot of small recyclers that receive plastic from local recycle bins. This is my market. The technology must be cheep, and can include a lot of labor by the local owner. The rainbow of colors from the #5 plastic is a condition. It has a cause. If I could figure out the root cause maybe I could discriminate upon the effect. Like cold fusion a good theory is needed to help with the harnessing the rainbow effect. light----> polarizer ----> bottle ----> polarizer ----> detector I always learn from doing. The light source is a LED light bulb. I have tested various bulbs and found that LED bulbs have a high frequency response. They can be modulated to eliminate stray light. I modulate mine with a half wave with a diode. Then signal is then passed through a 120 hertz filter. The filter consists of one resistor and one capacitor. It a cheep method that works. The cell phone adapter picked up and echo from the automotive speaker. I managed to solve this problem by splitting the phase of the stereo car speakers and putting the mike at the center-line of the car. I discovered a mike that picked up on a close spherical wave and rejected distant plain waves. It used a reversed wave dispersion effect through a small hole. A circular wave went in and a plane wave came out. Pretty neat microphone design. The combination worked the echo was eliminated passively even when the car radio was turned up loud. One manufacturer told me that passive echo elimination was unique, however, no one wanted a wired cell phone adapter. There was no market. I did learn about wave dispersion. Everyone wants to know about the latest sports score. I can't tell them. I have accumulated a lot of useless knowledge that no one wants. The only one who is interested is Jones. Frank
