This is an automatic ball thrower, based on NXT.
It can be built with the NXT 1.0 Set, + 3 40 teeth gears, and the bicycle wheels.
The ultrasound detector detects potential targets. The light sensor detects if a ball is present.
The two lower motors make the wheel turn with a 1:25 ratio, taking at least 2 seconds for reaching their top speeds.
The ball is pushed by a cart which is translated by the third motor.
When the ball touches the wheels, it is sucked and thrown.
The ball can be thrown to up to 2.5m.
This is my first LDraw model ...
Here is a video of a previous version (with the light sensor beneath the ball, which works well in a dark environment, but not when the robot is under a lamp of close to a window ...)