Ball posession: Roller (ball magnet) or vacuum?

[ubermeister]

How are you possessing the ball? How well does it work? Any innovations from the original ball magnet or standard vacuum design?

We went with a vacuum and are very pleased with the results. It uses an ungeared FP motor and a 5" shop vac impeller. The end-effector is a thin plastic food container. We can drive at full speed while maintaining control of the ball.

It seems most teams went with roller designs. I'd be interested to see how these compare to vacuum designs.

[robself705]

We went with vacuum but actually added a ball magnet to grab moving balls and push them into the vacuum. It works very well for us. We can easily score three shots in 20-30 seconds if balls are nearby the bot.

[joek]

we tried a ball magnet, but it didn't work, it just sucked the balls under the frame

[BradMello]

AIR Strike is using a vaccum.

You can see it in this video:

Click

[RMS11]

@ people using vacuums with those yellow funnels, where do you buy them? I looked around mcmaster but didnt see them...

[ravichauhan]

We are using a vacuum with a mcmaster carr plastic funnel. it worked but it will be more efficient to have a silicone one which we will attach before competition. we are using the fifth CIM for the vacuum because we are using the FP's somewhere else. Its speed is geared up 3:1. That will also be changed before competition to 5:1. What type of rpm are you other non-geared-FP guys getting

[fuzzy1718]

to those using the vacums, how are you stopping the suction when you kick? or are you?

[BradMello]

Originally Posted by RMS11

@ people using vacuums with those yellow funnels, where do you buy them? I looked around mcmaster but didnt see them...

Home depot is where we bought ours.

Originally Posted by fuzzy1718

to those using the vacums, how are you stopping the suction when you kick? or are you?

Just shutting off the vacuum prior to kicking equalizes the pressure fast enough that the ball will disconnect when kicked.

[Vince]

I spy, with my little eye, two dog toys....

[Austinmead]

how'd you make the vacuum?
we know you replace the old vacuum motors with the FP motors but we cant get it to work

[Alex Cormier]

Originally Posted by Vince

I spy, with my little eye, two dog toys....

How well does that work? We are currently using one window to a pvc roller with 35 teeth on the window and a 12 tooth on the pvc. It is a bit too slow for us to really grab the ball well.

[Vince]

Originally Posted by Alex Cormier

How well does that work? We are currently using one window to a pvc roller with 35 teeth on the window and a 12 tooth on the pvc. It is a bit too slow for us to really grab the ball well.

As of right now it is fairly effective but we are still maximizing the effectiveness.
The model that you see in the picture there is a 36:16 reduction from the denso motors with 2.5" diameter Vex wheels. We found that while driving backwards at full speed we cannot hold the ball as well as we desire, so we have changed the ratio to 48:10, to give us about 400 rpm. This may change again before our regional (week 5) but after a bit of testing we will know for sure.

[cziggy343]

for the florida regional, we had a shop vac that was powered by a fisher price motor. but when we get to palmetto, we are planning on testing our ball magnet to see if that works any better

[KrazyCarl92]

We used long rollers with latex flaps at BAE, which did not work well at all. We changed to vacuums for our week 2 regional at WPI and we were unparalleled in our ball possession. However, the ball had to be centered as we drove into it in order for us to gain possession. We were able to go around anybody once we got possession, using our swerve drive at full speed. Now we may be changing to something that's even better . I'll hesitate to call it a roller but it's along those lines...

[waialua359]

I'd look at the lack of rigitidy (softness) in addition to gripiness and speed of rollers.
I also saw a lot of FP and gearboxes for the rollers.
We used a CIM with a 2:1 reduction and adjust the maximum output via programming. We used 60% in SD, but for some reason had to step it up to 80% in AZ to achieve the same result.
Go figure.