I built a self-balancing robot using PID control with an Arduino Nano and an accelerometer MPU6500 with 3 stories of old CD player modules. The top layer will be used to hold the glass of water. This robot was able to balance on 2 wheels with the added top weight and irregularity of the water in the cup. I almost drenched my electronics that were located on the bottom storey several times.
Video Coming Up!