Transparent plastic detector

[leonel]

hi. I'm trying to build a transparent (at the beginning my plastic was black) plastic detector, but it doesn't work with emmiter / receiver neither with an electromagnetic solution. Does anybody has an ideia how to build it?

 

[Roff]

hi. I'm trying to build a transparent (at the beginning my plastic was black) plastic detector, but it doesn't work with emmiter / receiver neither with an electromagnetic solution. Does anybody has an ideia how to build it?

You need to think about the fact that you know what you are trying to do, and we don't. Try to put yourself in the mind of someone who has never heard of your problem. We don't know how far away it is, how thick it is, how big it is, etc. You need to provide much more information.

 

[dknguyen]

Isn't it obvious? Use sonar and not optical. Optical doesn't work with all plastics either...Just because you can't see through it doesn't mean that it won't be transparent to UV, IR, or some other wavelength of EMR! And just because you can see through it doesn't mean that it's opaque to UV, IR, or some other wavelength of EMR as well! But sonar? Sonar always work.

 

[jbeng]

You might be able to use a reflective optical (IR or visible) sensor of some sort instead of an interrupter-type setup...
Jeff

 

[mneary]

The plastic has some index of refraction. Don't point the emitter and sensor directly at one another, when the plastic enters between them it will bend the beam. (If everything is in the right places.)

 

[justDIY]

how about a feeler, like a piece of felt glued to a leaf switch?

 

[andy88]

feeler will not work in this case
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**broken link removed**

 

[Roff]

feeler will not work in this case
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**broken link removed**

The date of each post is in the upper left hand corner. You replied to a 3 year old thread.