Haha great that sounds perfect. Especially the stack of washers. Thank you for the inside information. I know a bit of computer vision so I think I will go with the optical approach instead of the electrical contact. With an automatic edge recognition I could easily read out the error. Only downside now for me with the Röslau wire seems to be that it is transparent but it should be fine. Do you remember the pulling force/weight? If not I will find out.


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