Ball Magnet

[dtengineering]

We stumbled upon the weirdly amazing effectiveness of backspinning the ball entirely by accident at our second team meeting. We'd just finished building a goal and some bumps and were discussing how to kick the ball. We've had good success with spinning "shooters" in the past, so the idea was to try a roller. (Zeki, one of our grade 12 students who has been on the team for four years is coming up with all sorts of really cool ideas this year. One, for a non-functional decoration... we're hoping to be able to fit into the weight and size limits.)

We took our old "Aim High" bot, laid it on it's back, spun up the IFI traction wheel and touched the ball to it. The wheel was spinning the wrong way to "kick" the ball... and the ball started to backspin and was held in place.

It didn't work particularly well, but I think its the first time we've ever figured out an essential component of the game that early. I think 1726 must have posted the ball magnet video about the same time, because we saw their video very shortly afterwards... and account for a few of those thousands of views.

So, of course, we figured if backspin is good... more is better. So we rigged up a test chassis using 6" AM wheels spinning at a couple thousand RPM and disovered that we could actually melt the outer lining of a soccer ball at those speeds. So we tried it with last year's intake mechanism, as 1726 had, and it worked much better... but we lost a couple days of build doggedly researching the "more is better" idea, and wondering why it didn't work.

Now we've got a 2" diameter aluminum roller directly driven by a 25:1 banebots running off last year's FP motor (about 600 rpm-ish) as our "final mock-up" and it's running okay. We've got a couple 26:1 P60 gearboxes from banebots on order for use with this year's FP's for competition. We used "magic tape" the black plastic wrap that sticks beautifully to itself, as a traction surface, but will probably go back to the rough top tread when it arrives, riveting it to the roller in a helical pattern in the hopes that it might help control lateral ball movement. We could probaly do with a little bit more speed, but can order a "faster" P60 and change it out in Seattle if we need to.

I can't believe how well this seems to work... mind you, EVERYTHING always seems to work well on the practice field.

Jason

P.S. We are trying this with an HS500 DTI ball, which apparently has a very similar finish to the HS300 ball on a carpet that, while not official spec, seems to be really close to spec. The HS500's shiny surface works, if anything, better, on this surface than the matte (and now partly melted in places) finish on the old soccer ball we borrowed from the PE department. They'll get a nice shiny HS500 in return after the season ends.