[sdiy] dave smith *instruments*

[Ullrich Peter]

Sorry I forgot to mention that there are also optical encoders from grayhill and other companies.
They cost about twice compared to the mechanical version but may work longer...

http://www.grayhill.com/opticalencoders/default.aspx

You can find types like this in some surplus stores:
http://www.grayhill.com/web1/images/ProductImages/Opt_Encoder_62AVD.pdf

The normal price at Farnell is about 40€ (about 55$) but I found them in surplus stores for about 5€ (7$).

Ciao
Peter