[FTC]: Help with shooting mechanism?

[JohnFogarty]

Originally Posted by cougarbytes

We're a brand new team, and have figured out using a programming language, but have been encountering problems with mechanically executing our ideas. So far, we have tried using two wheels rotating in opposite directions to propel the balls. However, even with gearing, we could not achieve the distance we were hoping and expecting. Our second idea was to pull back the balls like a slingshot, using surgical tubing. The problem we encountered here was that there was too much tension, and caused our metal to bend. When we lowered the tension, there was not enough power. We have another possible idea which uses a motor to pull back like a battering ram to release the ball. We are still thinking about our loading mechanism and have not tried any ideas for loading the balls.

Any ideas are appreciated!

I shall give you something we found works amazingly take a tetrix wheel and cut some Kydex sheeting into 1in wide and 4 inches long little paddles ziptie them to a wheel cut a space at one end for the plastic to fit on the wheel. Build a housing for it and it shoots perfectly.

[wilsonmw04]

FTC 35's test of our shooter concept. two DC motors geared up 1:27. One Word: Overkill. 21 ft range. we reduced the ratio to 1:9 and it's more manageable. Will post more this week

http://www.youtube.com/watch?v=ikLg0yrNTRw

[wilsonmw04]

going to try and post a photo of the gearing for the shooter as it is now: (cross your fingers that it works)



didn't work...
here's the link
http://www.flickr.com/photos/wilsonmw04/4100736107/

[cougarbytes]

Thanks, everybody! We're going to try some combinations of your ideas and our own.... once again, THANKS!

[JesseK]

Originally Posted by wilsonmw04

going to try and post a photo of the gearing for the shooter as it is now: (cross your fingers that it works)



didn't work...
here's the link
http://www.flickr.com/photos/wilsonmw04/4100736107/

If you want even more length-wise compactness, one of our kids came up with putting the motor mount on standoffs closer to the wheel. It works out very nicely for them. Maybe I'll get a pic up Tuesday night.

[lmnotran]

Awesome Design

[cougarbytes]

We have finally succeeded! We'll be posting a picture later

THANK YOU AGAIN FOR ALL OF YOUR FEEDBACK!

[PhilBot]

These high gear ratio spinners take a while to get up to speed. So wait till they are at full speed before shooting.

Note: In MD, some teams spun up their motors at the start of the match before Autonomous was actually enabled.

I posted a question on the FTC Q&A regarding the legality of this. As I suspected it's not legal for a couple of reasons. Only the servos are permitted to be powered before autonomous is run...

So you just have to wait before shooting.