The ball machine is 3'5" (104cm) tall and 2'9" (84cm) wide. It has about 3,700 pieces, and would have had more aside from the fact that I almost ran out at the end. The machine has seven paths, which will (according to my custom) be dealt with in separate steps. I also used the Stepper Lift, and will be making instructions once I take the machine down, since there are none on Instructables already.
So sit back, relax, and enjoy watching...Retrograde!
Note: Retrograde refers to the term retrograde motion, which is the process that make the planets appear to circle back on their orbits through the sky. I thought the name appropriate, because a lot of the ball machine's elements use circular motion.
The music in the video is Chopin’s Fantasy-Impromptu for piano in C sharp minor, Op. 66, CT. 46 and Mazurka for piano No. 23 in D major, Op. 33-2, CT. 73.
Step 1: The Stepper Lift
Since I always build on a red rod support structure, this lift posed several design challenges. I had to get the lift to connect to the rest of the machine! I settled on the 4 grey rod height because 5 red rods is roughly the same as 3 1/2 grey rods...which was the height of one side of the lift. I simply put connecting rods across the gap.
The other problem was the width - the yellow rod lift would not match my red rod structure, either. I solved this dilemma by placing the lift at a 45o angle to the rest of the machine. In this position, it fit perfectly. I curved the entrance and exit paths and voila! I could defy gravity!
Note: My gate mechanism may be a little different from I_am_Canadian's...that was out of necessity. There weren't any really good pictures of it, so I improvised... :-D
knexpert#10829476 created a motor housing and posted a picture in the comments thread.
Step 2: The Path Separators
It takes two balls to work. One ball rolls across the "trapdoor" floor, and is stopped by the rod just on the other side of the hanging floor. When the second ball rolls across the floor, it is stopped by the other ball. Its weight then drops the floor and the rod holding the other ball, allowing the first to continue along in one direction while the other is tipped in the other direction by a bracket placed below the separator. It took some time to get the thing to work perfectly, but once I succeeded it looked great! I call it the "Dropper Path Separator".
Step 3: Now to the Paths! - Path 1
Step 4: Path 2-The Wormhole
Orignally, I conceived it as lying flat, but decided the reset would be much easier if on its side, as it is in Retrograde. I modified it quite a bit from GeekBeam's design: I made the blades more solid, and made the frame opening more circular. I then mounted the modified diaphragm on a larger frame to match my red-rod tower structure. I then attached two levers, one on either side, to control the opening/closing. One worked fine with a golf ball dropped on it, but the other needed more weight. I then thought of the Zig-Zag, built one, and attached the two as one unit. The mechanism worked (for those who use lighter Knex balls, a ball arm may be necessary on both sides). I then moved the frame about until I got the current configuration, and built everything else from there.
Path 2 also sports a Classic Spiral using white snowflakes instead of yellow connectors (which I think looks even better than the original). The classic spiral leads to a "tire hole", which snakes down to the holding track of the iris (the iris was the first thing built, but the rest was the last path built, and I ran out of room...). The iris opens on a yellow connector path, which curves gracefully back to the ball return.
Step 5: Path 3
Step 6: Path 4
Step 7: Path 5
The path originates from the lower path of the Dropper Separator, rolls to the spiral, through a "Tire Hole" at the bottom, and onto a return path. Even though the glow-sticks don't light up anymore, it still works for my purposes.
Step 8: Path 6
As I tested the machine, I used golf balls. At one point, I plopped a Knex ball on the thing...and it went a totally different direction! It has to do with the ball weights. I modified Kariah's element by taking off the blue rod which normally tips the basket inward, and instead placed two Y-clips on the red rod it would swing past. The basket bumps the Y-clips and tips outward. Golf balls are so heavy that they immediately fall straight down, onto Path 6. But K'nex balls are lighter, and the gentle bump simply knocks them over the top of the red rod, onto Path 7. It was a welcome discovery, for I was running out of room for my elements, and this added much potential.
Path 6 goes through the Spinning Basket, and golf balls fall onto a length of my Green Flex Path back to the ball return.
Step 9: Path 7
Step 10: Additions by Request...
Many thanks for helping me improve this Instructable! :-D