For the last couple of months I have been building a copy of James Burton Sonic robot (2 wheel balancing robot),
It has been great to build, using lots of tools, and fun working in my shop. I made some changes to his design, I use more alum. parts and ready made wheels. Power tool batteries that are easy to charge and might even be cheaper. The brushless DC motors run on two Odrive motor controllers with a host of settings. The controller is a Teensy 3.6 processor that you program using the Arduino IDE.
My first "rolls" and "falls" with more to come https://www.youtube.com/watch?v=so3hPzTDSrI