DIY thickness measurement sensor

[yogece]

I would like to measure the thickness of a metal sheet in mm accuracy using a non contact sensor.can anybody show me the path?

 

[FvM]

Eddy current measurement is partly used in steel industry, besides gamma ray absorption which is most likely not applicable. Ultrasonic will need at least a coupler fluid and isn't strictly non-contact.

For ferromagnetic metals, I remember some exotic methods with contactless magnetostrictive ultrasonic excitation and detection in the metal.

 

[yogece]

Thanks FvM.
can i get micrometer accuracy in eddy current method?any article relevant to this?

 

[FvM]

I don't believe that it's possible. I don't have any references, just attended a presentation many years ago.