pic: My After Thought #6

6 wheel drive
4 Fisher Price for drive
Backspin Shooter
According to Inventor Physics it weights 104 lbs without electronics
It’ll soon have a wedge bridge manipulator

Hmmmmm…Fisher Price for drive. I thought of this a while back but got shot down because apparently the FP’s heat up like below 50% power or something.

Looks great so far!

I don’t think a 4 FP drivetrain would be a great idea. The CIMs are much better suited for the large forces, stall / near stall conditions, and heavy use of a drivetrain.

As much as I agree with the statements above about how FP motors in the drive can only end poorly, I feel compelled to mention that these motor were designed to act as the drive motors in kids cars. So, if you did the math to cool them properly, ensured they had a ridiculous gear reduction and NEVER went in a pushing match you might be able to make it through qualifications without replacing them.

Just my two cents…
Dan K

I can only echo the statements of FP motors in the drive. Unless you had plans for the CIMs elsewhere that take precedent, I suggest you reallocate them to the drive. Also, that is one interesting shooter. If I’m looking at it correctly, it would appear to be that the ball would have minimal contact between both the wheel and the compression hood. Correct me if I’m wrong please.

I don’t see your CIM motors in the CAD? Mind sharing about where they are being tasked?

  • Sunny G.

The FP’s were just a different idea instead of using cims. This wouldn’t be meant for any heavy duty pushing matches; just to go pick up balls and get on the bridge. This setup was actually lighter than using cims and I’d never done it before so I thought I’d try it. Also we’ve used FP’s before on a magic carpet for a school play and didn’t have any problems there. There would actually be about 3 inches of compression in the hood so it’s sufficient.

Pushing isn’t the only time you pull a large amount of current. Be sure to gear very conservatively or the likelihood of you frying a FP motor will be very high when accelerating (read, changing direction or starting moving). Honestly, the benefits of using a CIM is that they are darn near bulletproof and stand up to all manner of abuses.

CAN you use the FP motors? Sure! I just think that it would make more sense to use the CIMs for the task they are really good at and save the really high RPM FP motors for something they are better used for.

Do keep in mind this is just an idea and probably not going to happen; Just things that come out of my brain. So no need to beat a dead horse :wink: :deadhorse:

Actually, the second set of mounting holes on the FP transmission is the proper spacing for the 775s so all that you need is an appropriate pinion to make it work (this can be obtained by boring out the pinion that came with the FP motor). We did it in 2011 for our arm and it is a very good combination that, if done with four motors as shown here, could actually work quite well for light to medium driving. The 775s are much less prone to heating and should tolerate it, just have some extras on hand.

EDIT: What’s the deal with the CMU cam 2? Is it supposed to represent the axis camera or would you actually use a CMUcam?

Very detailed drawings, What program allowed you to do this as i would love to use it.

Judging by the fact that he cites Inventor Physics, he used Autodesk Inventor.

This CAD software is free to FIRST teams at the link below.

There is also a basic tutorial located here.


Have fun :smiley:

Much thanks

Yes, this is 2012 Inventor. It’s the standard rendering feature.

It was the only camera I had on file so I used it.