BUMP!!
break down what you think your machine teaches into chunks. Mechanics, electronics, programming, artistic expression, CAD etc etc etc. Then take one area at a time and break that down into small chunks, piece by piece. How would you explain what each piece does, how they interact with the other pieces. Chart it out and you'll start to come to grips about how you can present it over the course of a few months, hour by hours (class by class) HINT - you just have to be a few steps ahead of the students you don't need everything right at the get go.
Also, consider that you'd be educating as your class is building. So perhaps discuss mechanics first, physics, simple machines etc as you build the frame etc. Then as you add motors solenoids, etc you have the chance to discuss the concepts of electricity, electronics, soldering, troubleshooting etc. Add the Arduino or whatever runs the machine and you break that down into teaching programming.. (blinky, pins, if then, for loops, functions etc etc.)
A machine like this could be one giant learning project. Teaching technology is ALOT of prep work. . . Typically it takes 2-3 runs of a project to really get it going smoothly. (In my experience) Hope you get somewhere with it!
~Steve Maietta (11 year MS/HS tech teacher)