It's also a nice chance to show some pictures of my 332 cm(130 Inch, 10,9 feet) tall machine itself! It's the biggest I've ever seen, and also the biggest on Instructables. As you can see I had to take out one of the ceiling plates to fit it in.
In K'nex terms, it's 21,5 red rod blocks tall.
Step 1: The grabbing dropping arm
By sliding the counterweight up and down, you can tune the speed with which the arm moves.