King Pong

Please see the disclaimer for more information.

Note: The avi and mpg are realtime.

This was my submission for the contest "Accuracy over distance" held at BrickBots.

Robot Name:

King Pong

Score:

357

Brief Description:

Programming language: Not Quite C with RCX Command Center (Source Code)

Parts for "King Pong"

Brain:   1 RCX
Motors:  1 Electric Technic Mini-Motor 9V
Sensors: 1 Electric Rotation Sensor

Details:

When the robot is calibrated and has new batteries it shoots the Ping Pong balls about 2.40m (7.87f). The balls hit the inner target in about one third of the shots.

General:

KingPong uses a rotating arm to shoot the balls. As the arm is not able to accelerate to its full speed in less than a revolution the ball is kept in place until the arm has accelerated to full speed.

The left image shows the loaded robot. The ball is held in place by the axle marked with the long arrow. When the arm rotates the axle is moved by some gears and a worm screw in the direction of the short arrow, so that the ball falls down toward the revolving arm. The gears have to be adjusted to achieve the maximum distance.
The rotation sensor makes it easy to stop the motor before the bushes that are moved by the worm screw are stopped by Lego bricks.

King Pong Loaded King Pong before shot

The right image shows the released ball that falls down inside the four axles that serve as guides. The rotating arm shoots the ball back and into the target.
The motor to the bottom of the image serves only as weight, it is not connected! The motor that rotates the arm and releases the ball via some gears is the one to the top of the image.

Source code comments:

The program automatically shoots three balls, they just have to be loaded by the operator. A short sound indicates the point, when a ball can safely be loaded. That means when the holding axle has moved back into position to keep another ball in place. The program automatically shoots three balls, they just have to be loaded by the operator. A short sound indicates the point, when a ball can safely be loaded. That means when the holding axle has moved back into position to keep another ball in place.

Markus Matern, February 2002