Use Arduino as the controller and sensor MPU6050 to control the balance. Just add a simple Serial Bluetooth module and use a Bluetooth Serial Controller APP for Android Phone to make the remote control.
In the first version, the controller is Arduino UNO, then in the sencond version as the following video shows, just change it to Arduino Lenardo.
Now let's see how to make this robot step by step.
Step 1: Materials
3 × Acrylic Board
16 × Brass Stud M4x16
2 × Encoder Motor
2 × Motor Brakcets
2 × Shaft Coupling
2 × Wheel
1 × Arduino UNO (Arduino Leonardo in the second version)
1 × Motor Driver L298N
1 × DC/DC Power Converter LM2596
1 × MPU6050
2 × 18650 2600mAh 3.7V Li-ion Rechargeable Battery
1 × Battery Holder
Step 2: Build the Frame
Step 3: Install Motor Brackets
Step 4: Install Encoder Motors and Wheels
Then add 2 wheels on the motors.