Recycling Robot

[fallenangel]

I have to build a robot that detects aluminum cans, plastic bottles and glass bottles. They are all Coke products. What would be the best way that a robot can detect these materials?

I was thinking a sensor might possibly do this. Using a scale to weight each item is another option. Maybe even a slight pressure applied on each container will be enough to differentiate between the three.

Any ideas would be greatly appreciated. Thanks.

[bulkhead]

Aluminum conducts electricity--you could have a claw grab it and see if it completes the circuit (like a push button).  Then reaction to pressure can be used to distinguish between plastic and glass.

[Ro-Bot-X]

By the size. Each container has a different diameter and lenght.

[Admin]

Detect the materials (from a lack of anything)? Or detect which material is which? Or detect a Coke product from a non-Coke product?

[izua]

What about a can half-filled with coke, accidentally dropped? That might be bad for electronics.

[pomprocker]

id suppose a robot would need the same sensory that we have to detect it.

vision

[Jdog]

You could have a copper coil that all of the bottles pass. If the magnetic field changes, then it's an aluminum can. Then you can have the non-aluminum cans continue until they reach a certain point where an arm comes down with a pressure sensor on the end of it. You could program it so that if the pressure sensor gives a high pressure reading then it's glass, and if not it's plastic.

[Asellith]

Place two prongs on a robotic arm. If the prongs penetrate the material and it conducts its a can. If it penetrates and does not conduct its plastic. If it does not penetrate its glass