I did this back in 1985 using ping pong balls and an opto slot detector.
http://www.doc.mmu.ac.uk/STAFF/A.Wiseman/Acorn/BodyBuild/BB85.html
I did this back in 1985 using ping pong balls and an opto slot detector.
http://www.doc.mmu.ac.uk/STAFF/A.Wiseman/Acorn/BodyBuild/BB85.html