The inverted pendulum — hardest beginner robot

Try to balance a broomstick on your fingertip. You instinctively move your finger under it whenever it starts to fall. You're doing control engineering with your eyes and hand muscles.

Now imagine doing that with a robot, 100 times per second, using a gyroscope instead of eyes and motors instead of fingers. That's the balance bot — an inverted pendulum on wheels.

This exact problem appears everywhere:

• Segway — carried riders for 20 years using this principle
• Boston Dynamics robots — their legs are solving a variation of this every millisecond
• Rocket landing — SpaceX landing boosters upright is an inverted pendulum problem
• Drone hovering — keeping 4 motors balanced against gravity and wind

Your hardware: MPU-6050 IMU (angle sensor), L298N motor driver, two DC motors, Arduino. Your algorithm: PID control — the most important and widely-used control algorithm in engineering.

Let's go. This one rewards the effort.