The simplest way would be to make a ping pong ball scale "spud gun" using an electronic underground sprinkler control valve to shoot the ball. Ref: http://spud

The simplest way would be to make a ping pong ball scale "spud gun" using an electronic underground sprinkler control valve to shoot the ball. Ref: http://spudgunner.com/electronic.php http://spudgunner.com/electronic.php For motor based launchers, there are many ways: https://www.google.com/search?q=ball+launcher+mechanism https://www.google.com/search?q=ball+launcher+mechanism