CD ROMs are largely plastic enclosures that embed gears as well as fixtures for holding wires, motors, and other parts. At the heart, there's a laser, an optical sensor, and a weird motor that is difficult to control but extremely efficient. I found the most useful information about these from an Australian RC Plane hobby board. They have detailed plans how to disassemble some of these motors and rewire them, to make them easier to control for a remote control toy plane. The electronics discussions are a little sketchy, to the point where I've started wondering if there are electrical engineers on the Web anymore.
Having some of the skills makes these projects seem easier. If you count it out, the range of skills is much wider than you'd expect, and depth in each varies quite a bit. Here's a short list that comes to mind-
- programming in a C-based language (if you have an embedded controller like an Arduino)
- Some electronics
- Some mechanics
- Some CAD for printing a circuit board (for finished projects) or just a well though out design for creating the circuit more permanently.
- Some CAD for designing the 3D printer files to make the shell out of plastic, or the ability to machine this stuff from your material of choice.
- The problem domain you're working in. If it's a quad copter it's some aerodynamics. If it's a plotter of sorts, it's also going to involve a lot of gear sets and geometry.
- go to an outstanding STEM school
- Be around people who are good at this stuff
- Access to tools and materials for hands-on work with this stuff, some of which is fairly expensive
- Have a place to experiment with this stuff
After years of addressing the "Digital Divide" by sending computers to schools, I think we missed the real point. I don't have a solution, but just a growing awareness of what doesn't seem to work no matter how many resources are misdirected at solving the wrong problem.