recently on Pinside a pinballer put the call out for help with a mechanical system to help a fellow pinballer in a particular league that only had one arm. Ben Heck came across the thread and wanted to help. He stepped it up and made an awesome system and sent the "one arm bandit" system over to the guy in need.
check out Ben's 28min video of how he made the whole system.
shows 3d design, printing, electronics, a small computer and PINBALL