Check out LittleBits: http://littlebits.cc/. Really amazing way to get kids into an engineering mindset. They’re basically modular electronic circuits that you can easily combine in an infinite number of ways. There are over 50 different modules you can use to build things. Sensors, motors, switches, knobs, lights, etc. Think Legos for engineers.
I bought the Korg synth kit so that me and my kid can build analog modular synthesizers without the messiness of needing to solder. It says ages 14+ and she’s only 3, so maybe I actually bought it for myself, but still…
Edit: forgot to mention that they’re open source and all of their schematics and PCB’s are available on their github page
