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I've been looking for ideas on how to launch a ping pong ball a small distance (< 1 metre) for a game. Solenoids look like they might be useful but I'm not 100% on what force/type I need. I can mount it under a base and have the balls roll over it, with a pin pushing the ball up a ramp to it's target.

As it's only a ping pong ball, it should be light. I was considering something like this: http://www.adafruit.com/product/412

Am I along the right lines? Or should I go back to the drawing board.

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  • \$\begingroup\$ How much does it weigh (what is it's mass?) and what initial acceleration do you need to move the ball? Force = mass x acceleration. \$\endgroup\$ – Andy aka Jul 16 '14 at 11:41
  • \$\begingroup\$ Not sure if you're aware but most sports balls have a standard weight and it looks like it's 2.7g for a table tennis ball so you won't need to weight one. \$\endgroup\$ – PeterJ Jul 16 '14 at 11:59
  • \$\begingroup\$ Having said that now I think about it I don't think it will be quite as simple as calculating the acceleration, I think you'll need the initial velocity so it might be something you just need to try - I can't think how you'd calculate that from the datasheet because it will depend on the actuator speed I believe. \$\endgroup\$ – PeterJ Jul 16 '14 at 12:16
  • \$\begingroup\$ @andy-aka These are standard balls so roughly 2.7g as suggested by peterj. I'm not too sure on what acceleration we need but the distance required would be up to 1 metre. \$\endgroup\$ – MrNorm Jul 16 '14 at 12:52
  • \$\begingroup\$ Time to do some kinematics... \$\endgroup\$ – Matt Young Jul 16 '14 at 14:40
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A solenoid could work. Another thing that could work is using compressed air. A ping pong ball in a tube that's slightly bigger than the ball's circumference with an electrically controlled valve could do it. You would basically want to replicate a t-shirt cannon on a small scale, and use paintball air tanks to get multiple shots before having to recharge. Changing the length of the tube would also let you have fairly good control over how far/fast the ball goes (longer tube = longer time that the force is applied to the ball and so greater acceleration). I think a solenoid would be a simpler option though. I would get some large ones and experiment with the repeatability and power needed to get the ball where you want to go.

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