Ball Shooter

Purpose:  
To explore shooter design concepts in FRC.
To develop an adjustable shooter prototype that can be modified for different game pieces.
V1: Double Shaft Configuration
6032 Adjustable Shooter Prototype - Double Flywheel Configuration
Design Notes:
80/20 structure is rigid and adjustable.
Bearings and motors mounted to frame with 3D printed brackets (modified HYPEBlocks).
Large Colson wheels (4" x 2") will hopefully provide grip and sufficient angular momentum.  Wheels can be easily swapped out.
Falcon 500's with a CIM Mount, 1:1 VersaPlanetary
1/2" Hex VP output with shaft coupler (shown)
        Or
VP Universal Female Output with female 1/2" Hex adapter
Adjust wheel speed with servo testers.  Slower on top and faster on bottom should increase the angle of release and give it some backspin.
Consider adding side guards and a feeder ramp (wood, lexan, cardboard, ...) for safety and so balls are fed in a consistent manner.
This could be modified as a hooded shooter, and modified for different sized game pieces.
Access the Onshape document for more details.
Sketch & Cut List
3/23/2021
When mounting anything to a Falcon 500 motor, you need to use very short screws.  0.5" is too long because it will bind with the motor internally.
Use #10-32 SHCS, 0.375" long to mount a CIM adapter to a Falcon.
3/24/2021
Proof of concept
Next steps:
Adjust wheel speeds to "dial in" on a target and evaluate consistency. 
Consider adding flywheels to shafts, see if that impacts consistency & range.
3/26/2021
We added brass flywheels
The flywheels gave us a more consistent shot when sending many balls in succession.
Students adjusted shaft speeds to aim for a specific point on the wall.  They started with slow shaft speeds and increased the speed of each motor one at a time, dialing in on the target.
Next Steps: 
Integrate this mechanism onto a robot.
Work on ball intake.
Work on ball storage & how to feed them into the shooter.
4/15/2021
Integrated the Shooter onto a prototype robot.
Feeder mechanism supplies balls to the shooter wheels.
Already have some backspin before entering the shooter - this is good.
Next Steps:
Continue to "work backwards" & think about how balls can be fed into the feeder mechanism.  Maybe from the front of the robot, or maybe behind the wheels.
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V2: Hooded Configuration
6032 Adjustable Shooter Prototype - Hooded Shooter Configuration
Design Notes:
Similar to the Double Flywheel version above, modified by removing one shaft and replacing it with a hood.
May need to use second motor and/or speed it up with a belt & pulleys.
Insert dowel rods in holes or use long standoffs/churro/thunderhex.  Fasten a flexible polycarbonate sheet to the dowel rods to create a smooth hood.
Adjust compression and release angle by using different holes for the dowel rods.
Inspiration
Team 5013 Trobots
This shooter uses two sets of wheels.  You can control release angle by adjusting the speed of the top and bottom wheels.
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Ri3D Team 1.0
Here is a prototype version of a similar idea to team 5013.
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3847 Spectrum
​This concept is made with Protopipe.
From the Spectrum Protopipe documentation
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2706
This design features a simple over the bumper intake, low profile, and shooter with a non-adjustable hood.
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5712 Gray Matter Robotics
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1690 Orbit
This team was able to adjust the angle of their entire shooter in order to adjust the release angle.
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6328 Littleton Robotics
Team 6328 has an amazing shooter, with full CAD available in Onshape.  We can learn a lot from these details in CAD.
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