The Old Ping-Pong Ball Levitation Trick


[Jacob] has put a slightly new twist on the levitating ball trick with his ping-pong ball levitation machine. We’ve all seen magnetic levitation systems before. Here on Hackaday, [Caleb] built a Portal gun which levitated a Companion Cube. Rather than go the magnetic route, [Jacob] levitated a ping-pong ball on a cushion of air.

Now, it would be possible to cheat here, anyone who’s seen a demonstration of Bernoulli’s principle knows that the ball will remain stable in a stream of air. [Jacob] proves that his system is actually working by levitating ping-pong balls with different weights.

A Parallax Ping style ultrasonic sensor measures the distance between the top of the rig and the levitating ball. If the ball gets above a set distance, [Jacob’s] chipKit based processor throttles down his fans. If the ball gets too low, the fans are throttled up. A software based Proportional Integral Derivative (PID) loop keeps the system under control. A graph of the ball distance vs fan speed is displayed on an Android tablet connected to the controller via USB.

When [Jacob] switches a heavy ball for a light one, the lighter ball is pushed beyond the pre-programmed height. The controller responds by reducing the fan speed and the ball falls back. Who said you can’t do anything good with a box of corn dogs?

15 thoughts on “The Old Ping-Pong Ball Levitation Trick

  1. Come on people, it’s time to start negotiating product placement on your hack write-ups. Ho-Hos or Moonpies might be willing to pay to get their product placed in front of a bunch of geeks. Heaven knows we’ve consumed enough of them.

  2. So when a heavier ball is placed in the air stream it speeds the fan up to maintain height and when a lighter ball replaces it the reverse happens? So if you monitor fan speed and correlate it to the force the fan produces in the air stream you could weigh your balls.

  3. If you want to test that principle but don’t have any device at hand, save for the ping pong ball itself, just turn your head 90 degrees up, keep the ball a few centimeters over your mouth, then start blowing and release the ball. It will float in the air until you stop blowing.

    1. Was thinking the same thing. Then of course you went home and tried it yourself just to find out their’s was hooked to the blower side of things. Mom was never so mad as to find her nice vacuum plugged with a ping pong ball.

  4. Jacob and his company were in the Startup Tent at the SF Maker Faire, you would not believe how many kids were excited about the demo.. some kids were able to put the lighter ball over the heavier one to get dual floating ping pong action! I don’t know if anyone here has seen the other demo they programmed that levitated 16x ping pong balls..source code included, but sadly no Corn Dogs:

  5. And Bernoulli’s principle gets misused again. According to Bernoulli’s equation, the wings on planes are too small and inverted flight is impossible. Look instead to the Coanda (and Magnus) effects.

      1. I believe the real mystery here is how the fans in the box keep the temp low enough to preserve the corn dogs. Perhaps it is a brave new principle to be explored, or merely high sodium content. Regardless we should move fast before the patent trolls move in, No one like to jam on chewy c-dogs.

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