This bottom view shows the wheel motors and wheels, and the vacuum system. Confetti enters through the wide slot at the front (right side of the image), filling the triangular chamber and the center rectangular chamber. A wire screen inside the chamber provides lots of sucking surface area. Suction is provided by the two Dustbuster fans at the rear (left). The center chamber is covered by an aluminum door which is controlled by a servo (like those in model airplanes). The servo is inside the diamond-shaped chamber, and not visible without the door open and a dental mirror. :v)

In a modification performed after these photos were taken, a second servo was installed outside the vacuum chamber, with a shaft leading into the chamber and a wiper blade that was to help push the chaff out the door. It didn't help much.