Help with the Pingpong-bot

Well my holonomic mini bot and dragster didnt work out as well as i liked so I thought i would try to make the pingpong bot from the Vexlabs gallery. I looked at the vid of the shooter, but i cant figured out how you can make that beam bounce when the axel rod moves off it ??? any ideas?

well, vexlabs sell a rubber connector, and that’s what I always thought that they used…

guess so lol.

I really dont feel like spending 7 bucks and $5 for shipping for 4 rubber thingys that I’ll probably only use once, so im trying to figure out an easier alternative.

try using small rubber bands

i used a plastic spoon in mine

oh I didnt think of that, sounds like a good idea :slight_smile: thanks

Don’t under-estimate the power of elastic bands. :smiley: They are cheap, plentiful, and if used together in a large enough bunch, you can launch raquetballs 6-10 feet with Vex. Here is a picture and a quick video (only 0.9 Mb) of a quick continuous-rotation launcher-arm that I built back in January 2006.

The way it worked was by constantly being rotated by two motors. When the claws would reach the bottom (where it would pick up a ball), a pin held back the launcher to give the ball enough time to roll on, in addition to building up force in the elastic bands. (E.g. the thrower claw would stop rotating, but the center would continue to keep rotating. The claws had a hinge inside the claw, and when they stopped moving they would build up force in the elastic bands, which would then be imparted into the ball.)

When the force was great enough, it was enough to force the Lexan (similar to Plexiglas (acrylic), except that it won’t shatter. You can buy it at Home Depot.) piece past the stopper pin and it would launch the ball. Voila, a ball launcher! :smiley:


(Only one of the throwing arms in this picture had the Lexan stopper piece on it.)

And here is a video showing how it works by hand. (It worked a lot more effectively powered by the Vex motors.) http://www.team228.org/video/vex/continuous-rotation-throwing-arm.wmv