Lego Ping Pong Ball Shooter

The gearing is the really interesting thing here. The ratio is 1:25 and that's turning two wheels at once. A single motor couldn't handle it. Two motors could do it, but barely and when I put the ball in it almost stopped. Three motors worked OK but still slowed quite a bit. Four isn't much of an improvement, sadly, but at least is symmetrical. All 4 motors are turning a single gear train connected to both wheels.

The ball goes up about 4 ft, which by my calculations means it was traveling at ~ 5 m/s ( 11 mph) when it left the muzzle.

Category:

Howto & Style

Tags:

• lego
• machine
• ping
• pong
• ball
• shooter

[jroz0492]

ok iv been working on a ping pong ball thrower in class and i have the same disign as urs except sidewase i tried a big to small geer ratio with the bigger tires and got ok results but now im in the process of trying a big to small to big to small (same concept as urs) the only problem is like u said it takes a long time for the motor to get up to speed but hopefully ill finish tomorrow and have good results

have any suggestions for trying to make the ball go farther (also only have 2 motors)

[desiredusername]

If you just want distance, a catapult might work better. But whatever you come up with, I'd like to see a video of it.

[jroz0492]

is there any advantage to using thinner weels with a bigger radius? or would the wheels used on this one be best?

[desiredusername]

A larger radius will have a higher linear speed at the rim. But thanks to conservation laws, it'll also be harder for the motors to maintain that speed when you toss in the ball. I actually did try larger wheels briefly, but the motors couldn't keep up. Maybe more motors?

Also, the larger radius wheels have a smaller width, so you'll need to stack a few to make them as wide as a ping pong ball.

[freakoffer]

Now, if you only attached a rotatier to that crazy thing... Put a shoulder strap, add a handle and a trigger... Hmm, maybe its too dangerious and the airplane company might ban that idea. But hey, DID ANYONE SEE THOSE LEGO PIECES IN THE BACKGROUND?!? HOLLY CRAP!

[desiredusername]

I've got all those pieces (and many more) in tiny drawers and on top of a special table now. The table sits 3. It's pretty awesome.

[gizmo00000000000]

you should use a golf ball and then shoot it at people.

[KaroMassudi]

when you made the ball fly upwards , i like giggled a little :)

[wooperpro]

you just made flywheels! :D

[RiderBeFigure]

use it in war that should help

[gedd11]

a more time consuming way to make Hotwheels tracks

[RoShAnOWNEDyou]

look, this is pro made.

[emogta]

awsome ball gun

[RGBfanatic]

nice. good idea, and try a self reloading one, or one that has a light sensor that senses the ammo coming into the shooting area. then the sensor would signal the NXT 'brain' and it would turn on the tire rotation, and lift the pingpong ball into firing position. ^.^

[SparksLoog]

I tried something like this but failed.

Is it the gears?

I need to do that because of slowness.

Oh! I get it. It is math? More rotations?

Am I right?

[TheBastard97]

Pretty useless but cool :D

[CHEETO3210]

awesome!! well done my good man!! good show!! lol

[FredDeadz]

i constructed a lego spinning top, out of lego knex and a motor that makes a car move when pulled back, and a wheel,

success