Do you remember those building toys called K'Nex? Well an engineering student at the University of Colorado (CU) named Andrew most certainly does. He actually managed to build a fully-functional pinball machine using only the tools available from the plastic building toy. Andrew spent over four months meticulously planning and building his K'Nex pinball machine that has functioning flippers and a plunger that is capable of launching the ball into the field of play. It also has a small gearbox that powers the two small chain lifts that help move the ball between the different features of the table.
In all, the table has three main features that create the dynamic elements of the pinball machine. The first of these is a hole that leads to lifts. From here the ball runs through a tubed path that runs around the entire machine and brings the ball back to the main play field.
The next feature sits next to the left flipper. It actually drops the ball all the way underneath the machine where a lift picks it up and brings it all the way back to the top.
The third feature, and the one Andrew says was the most time-consuming for him, is another hole in the floor of the table. The lift brings the ball to the top and drops it in a holder. The player needs a second ball to cause it to release and then both balls are carried back up to the top. The balls are then dropped onto the tracks where they will descend the entire machine through various loops and other cool obstacles.
I asked Andrew what made him want to dedicate four months of his life building this thing and his response summed up design and ingenuity perfectly. "I wanted to build this to challenge myself in what I could do with a little determination. It was something nobody had built before, and I figured it would be awesome to have a working pinball machine in my basement that I built from scratch."
The video below shows exactly how the machine plays.
Source: Instructables