Trying to shoot a ping pong ball..

Scoot

Im trying to launch a ping pong ball from a robot for my sophomore engineering class.· I want to strike the ball, much like a golf ball return mechanism in a putting cup works. My question is, is that a solenoid motor, and if not, what is it.· Thanks

Bruce Bates

Scoot -

It may well be a solenoid, but I'm not familiar with the term "solenoid motor". I am familiar with a rotary solenoid, but that seems unnecessary in this application.

Regards,

Bruce Bates

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Unsoundcode

Hi Scoot, I'v never tried it but with a certain amount of modification I would think using a solenoid to actuate the rod on a small pneumatic piston valve and·using the expelled air to blow·the ping pong ball down a tube would give better results than striking it with a solenoid, I think it may tend to penetrate the ball it's something you would have to try.

Jeff T.

allanlane5

Having done something like this with Mindstorms, the key is using some 'energy storage' element (like a rubber band) on a lever. Then, you 'pull down' the lever with a cam on a servo. When the cam slips off the end of the lever, the rubber band 'snaps' the lever back into contact with the ping-pong ball, shooting it into the air.

The servo is then moved back into the 'load' position for the next shot.

Anothe solution is to use a solenoid -- a piece of steel with springs inside a coil. When you energize the coil, the piece of steel shoots to the middle of the coil -- and the far end can contact a ping-pong ball. This can take more instantaneous current than the servo approach, however.

Unstable

I am working on something a bit similar. (exept instead of ping pong balls, airsoft ammo)

my design is going to have a large capacitor charge up, then to launch discharge through a SCR (silicon control rectifier) into the solinoid.

the circuity is fairly simple and I tested a NTE5463 driven directly off a stamp2 and it seems to work (haven't tested with a solinoid yet as I have to build it)

I also tested it with a opto-isolator setup, (a set of radioshack IR led and phototransistor) to prevent the stamp getting surged from the high power discharge.

if you want I can draw up a simple schematic.

--Unstable

Mr. Richard

a different option is to have a pneumatics system. I currently have a robot I drive around my classroom. I have a feeder mechanism that holds Starburst candies. There is a servo that places a candy in a cup at the end of an arm. There is a solenoid that controls a piston with about a 2 inch throw, this shoots the arm sending the candy flying to the lap of unsuspecting high school kids. (about ten feet away) The parts I use are from SMC corporation. There is a small air tank that is filled with a bicycle pump, 4mm airline tubing, a switch, regulator, solenoid and piston. soon you can read about it in the completer projects area.

If interested, I can get you catalog numbers while at school

have a fun day
Josh

Tom Walker

..or if you really want to go with the "golf-ball-like" idea, how about a motor with an arm that strikes the ball. Ping-pong balls are light and don't need a lot of impact force to launch...one rotation with an arm with a decent mass should move it quite well...I could see it done with a hobby 3V motor and a switch or encoder to let you know when the shaft has made a full loop...control it with a transistor...

Just noodlin'

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