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Unread 16-02-2012, 10:47
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Re: Wheel shooter gearing

Quote:
Originally Posted by Ether View Post
Method3:
Fasten a small zip-tie to the motor wheel, then mount a small piece of card stock so the zip-tie hits it and makes a clicking sound once per rev. Record some audio of the wheel spinning then digitize it and run frequency spectrum analysis software to locate the frequency of the clicking.
hmmm... this is the only method we haven't used so far this year for our shooter, and now I want to try it!

We used a strobe (borrowed from work) on our prototype to figure out how fast it was going (it's easiest to tape a small strip of white paper on the wheel to to help you know when the action is stopped), since we were powering it with drill motors, and everything else seemed to complicated/long to figure out.

We measured the current to make sure the motors weren't going to burn out, and once we had that number, it was a fun little exercise figuring out the exit velocity of the balls (assuming no slippage).

We have encoders on the shooter to allow full PID control for accurate shooting. While I haven't seen it yet (programming has only had access to the robot for a couple of days), we are supposed to have distance detection working, and should be able to automagically adjust the shooter speed for a perfect basket every time.