What Sensor to Use

Hi, I'm planning to do another project which involves the use of multiple sensors. One of my project's function is to detect plastic. Are there any sensor or even camera that can detect plastic and also cheap that I could use?
If this topic is better on the other threads please tell me. Thanks!

No, no such sensor.

But just for completeness, define "plastic".

jremington:
No, no such sensor.

But just for completeness, define "plastic".

Synthetic material that can be molded when soft and formed into a solid shape

That are not properties that are measurable/detectable by a sensor.

wvmarle:
That are not properties that are measurable/detectable by a sensor.

How about a camera? Are there any programmable camera or camera that can learn that is cheap?

How can a camera distinguish a white sheet of plastic from a white painted sheet of metal?

wvmarle:
How can a camera distinguish a white sheet of plastic from a white painted sheet of metal?

Cheap small camera which a function like the ones in automated cars etc. Where the camera can learn via pictures that makes them learn (somehow).

sioty:
Cheap small camera which a function like the ones in automated cars etc. Where the camera can learn via pictures that makes them learn (somehow).

I would imagine the cameras used in automated (self driving?) cars are not 'cheap'.

So how do you imagine an Arduino could carry out AI type learning to tell the difference between painted plastic and painted metal, even assuming it would be possible ?

srnet:
I would imagine the cameras used in automated (self driving?) cars are not 'cheap'.

So how do you imagine an Arduino could carry out AI type learning to tell the difference between painted plastic and painted metal, even assuming it would be possible ?

What about Capacitive Sensor?

That may be able tell apart plastic from metal but not from wood, or plaster, or glass. But now you have to touch the object with the sensor or no chance.

wvmarle:
That may be able tell apart plastic from metal but not from wood, or plaster, or glass. But now you have to touch the object with the sensor or no chance.

It's okay if it also detects wood, plastic, or glass. How close should the sensor be with the plastic, wood, etc. to sense it? (in centimeters would be fine)

A capacitive sensor tells apart metal from plastic/glass/wood because it detects the first, and it does not detect the others. Unless you're talking about a conductive plastic as it will detect that as well.