Snap Circuit Kits make good introductions to electronics. Think circuitry LEGOs.
I have ran into similar problems in the past. I hit the ceiling of the "technical" promotion track, stayed there for a few years and finally hit the max salary band. If I wanted another promotion/pay increase I would have been forced into a project management track. I finally chose the option that wasn't being offered - I gave my two weeks notice and left for a new employer.
Communicate with your employer - tell them where your interests are. Talk to your boss, dept director, HR to see if there are any options to shift the promotion into a technical position. At the same time, if you are committed to keeping a tech job, keep your options open by seriously looking for new job opportunities. If you find that you are out of options with your employer, its probably time to move on.