You need undergraduate engineering. Thermodynamics, circuits, mechanics, diffy q. Granted you will have all of your gen eds done, but you need to take these prereqs to use CAD and design things. If you think you can think like an engineer then forget what your background is. Everyone is an individual and just because you know sociology doesn’t mean you can become and engineer; in addition, an engineer could conduct research and write a dissertation on social sciences without an undergraduate degree in it.