Dave,
I'm with Mike (mhulbert) on this one.
A curtain opener is not unlike a garage door opener, except it works in a different way.
The principle is the same though, with limit switches and so forth.
I seem to remember John (Reno) talking about knowing things outside of the electrical trade.
This is one of the places that Electrician's should be able to go.
Mechanics and say, servo motors, etc.
You guys should know this stuff, or at least be able to pick it up pretty quickly.
It's all very well being a Master Electrician, but passing an exam is nothing without real world experience.
Prove me wrong.