Dean Kamen, unveiled the Segway Human Transporter in December 2001. It balances with the help of dual computers, two tilt sensors, and five gyroscopes. (The gyroscopes do not affect the balance; they are merely used as sensors, see detail below.) The servo motors rotate the wheels forwards or backwards as needed for balance or propulsion. The rider accelerates or decelerates by leaning forward or backwards in the direction he or she wishes to travel. Video after the jump.

Segway HT, Human Transporter