Re: motor for ball Shooter?
 

So I'm guessing that teams using cim motor for a shooter/cannon will only be using a total of two cim motors for their drive train

Re: motor for ball Shooter?
 

Fischer Price or CIMs are really your best bet. We've been prototyping all week in different configurations using last year's kit wheels. We were able to get a ball shooting beyond 15 feet, however, we don't really think we'll be going for that kind of distance in our final design.

As others have said, a direct drive from the small CIM would do just fine for shooting 5 - 10 feet. I would advise everyone to try out different materials as we've found that some materials react much better with the ball than others.

Re: motor for ball Shooter?
 

I always like the design MARS 1523? used for their shooter in 2006. It would work great with these balls I think. A design like this would allow you to use a less powerful slower spinning motor like a bane bot.

Re: motor for ball Shooter?
 

Thanks for the kind words about our 2006 robot design, Ball-istic.

MARS, Team 1523, accomplished that with a one-way bearing, a little bit of surgical tube, and a window motor. It wasn't a winning design of the season, but it was gentle on the game pieces and worked very well for us. It would even throw balloons without breaking them!

I'm not sure we need that kind of power in this year's game. 30 ft into the upper goal is a little too much. That center post on the trailer is going to prevent many a ball from staying in the trailer.

Re: motor for ball Shooter?
 

We just made a test stand using two CIM motors direct drive with 6 in Skyway wheels. They were set at about 35 degrees (low ceiling) and were 4 ft off of the ground and we were able to land a ball in a trailer located 13 ft away. These were mounted horizontal and our final design will be vertical. I did notice that if a hole portion of the ball happened to hid the spinning wheels the distance was greatly reduced. We will be using four wheels to contact the ball to reduce this problem and may use 8 inch wheels instead of 6 inch. The CIM motors seemed to come back up to speed very quick with out gear reduction and a well balanced wheel.

Re: motor for ball Shooter?
 

We made a prototype last night with a wood frame holding (4) 4" RC racing wheels, the left and right of which were both direct-driven off of their own CIM. Unfortunately, these wheels were all off-roading wheels, so when we turned on the motors, the tires got really skinny and the wheel diameter doubled :ahh: It was pretty scary, but managed to shoot a regular inflatable ball about 60 feet, and the orbit ball around 10. When we stop using maximum speed and motorize the other two wheels and replace all of the tires with road flats, the ball should be a little better controlled (and the rig should be a little less insane).

For reference, the Fisher Price motors are 2/3 the power of the CIMs (1/3 horsepower). Due to the low-friction of the field, there's very little problem using them on a drive train, as long as you monitor the wheel speed vs. motor power to make sure something isn't jamming your wheel and burning up your motor (the magic smoke is hard to put back into the FP's, that's their drawback over the CIMs).

Re: motor for ball Shooter?
 

If you can afford to part with a CIM or 2 (and with the low traction this year you most likely can) I would recommend those for the shooter. They're easily the most powerful motors in the kit and have a high RPM if you don't want to gear them down much. There's also a number of transmissions available from AndyMark that will allow you to get different gear ratios if you need a larger reduction than what can be done with pulleys or sprockets easily.

Whatever configuration you use make sure to gear your motors low enough that they can get the wheel up to speed quickly and not jam. We had an effective tracking algorithm and driving robot in 2006 but the death of our system was an under geared shooter that could not fire a ball more than once every 2 seconds or it would jam.

We're going all out on our shooter this year, 2 CIMs in the current test setup and we're considering adding a third if we don't use it anywhere else. This is for our specific design though and I don't think that much power would be useful on most shooters.

Re: motor for ball Shooter?
 

I think shooting (goal) for 15 ft is fine, if you can adjust and slow your CIM speed based on distance.
On reading another post about having a backspin on the shooter wheel, they made a huge difference, in our ability to score in the trailer.
Our team is hoping to finalize our wooden shooter design prototype tomorrow and work on a feed system. :)

Re: motor for ball Shooter?
 

A single CIM would actually be significantly more powerful than the single large CIM you used in 2006.

Re: motor for ball Shooter?
 

I am kind of surprised people are investing so much motor power in their shooters. 1 CIM seems like plenty of power to me.

Based off of our prototype shooter, 1 CIM spinning at 1:1 ratio with a 6 inch wheel threw the orbit ball ~30-35 feet, which seems to be awfully overkill for this game. This was feeding ball after ball right after another through the shooter wheel.

Re: motor for ball Shooter?
 

How much compression were you running on the ball? We seemed to have settled on 2"

Re: motor for ball Shooter?
 

Can you provide details on your setup? Our prototype has one CIM per side @ 1:1, driving stacked 2008 KOP wheels spaced ~6" apart. A piece of ductwork is acting as a barrel to provide a little forward spin. At best, we've been able to hit targets as far as 15 ft.

We're planning on using wider, softer wheels in the final design to get more surface contact with the orbit ball and will be driving the entire system with 1 CIM.

Re: motor for ball Shooter?
 

What Brandon forgot to mention is that the NU-TRONs have been playing with ORBITS for a very long time, and have some magic secrets they can't tell us about :)

Re: motor for ball Shooter?
 

We have a gap of 7.5", given the ball to be between 9"-9.375", from the numbers I've seen and the measurements I've taken, its around 1.5-2.0" compression.

Re: motor for ball Shooter?
 

Thanks for the tips on the shooter motor slowdowns. We don't have a CIM available for the shooter, and our window motors are being used for our conveyor system. So we're down to the FP & Banebots motors for the shooter.

For our setup, we're considering 2 FP's into AM Planetaries (3.67:1) and a 1:1 pulley ratio off of that. The roller radius is probably going to be 1", and will not be a single roller but instead will be another sort of conveyor belt. The hope is that this gives the ball more acceleration time and contact area, therefore the holes have less impact on the distance. We don't want max distance as much as we want a consistent shot.

Does anyone see any glaring deficiencies or oversights with this setup?

Also, didn't I read somewhere that with AM plaction wheels you could put a 5" PVC pipe in between the separated wheel to create a much wider wheel? Or am I dreaming? I can't seem to find that anywhere on these forums or on AM's site -- but I think that'd be a better idea than mounting 4-5 skyway wheels side by side. Then you could also easily mount your own tread.