I built this balancing robot using a MPU6050 gyro and an Arduino nano board. The chassis is just a perfboard (I once mistakenly ordered some without copper) and the drive is built using a dc motor and gears from a cd drive. The motor is controlled by a h-bridge with bipolar transistors i built. The regulation code is mostly adapted from similar builts i found on the internet although i changed it to not use PWM to control the motor cause it was too weak and this way it works better even if its pretty shaky.
Enjoy this project?