Team 254 Presents: Dropshot Technical Binder 2016

[Ashwin Adulla]

Originally Posted by apache8080

What other wheels did you guys try out for the flywheel?

Do you guys use laser cut wood for majority of your prototypes? I assume that this makes prototyping easier and more accurate.

When is your code going to be released?

Thanks for this incredible resource.

We bagged and tagged our robot with 2 4" Colson wheels acting as our shooter. At CVR, we used 4 4" Colson wheels. At SVR and Champs, we used 2 4" Fairlane wheels with safety wire wrapped around it to stop it from expanding a significant amount past 5000 rpm.

Yes we did use a laser cutter for prototyping with wood and it greatly aided our prototyping process as we were able to quickly CAD and test different variables for our flywheel shooter (pg 13) such as hood angle, pulley ratios, ball traction, and moment of inertia. In addition we did use the laser cutter to test out different intakes and also to cut the hubs for our mechanum wheels.

As for the code, our programming team is performing a code clean and is planning to release it soon.

[Knufire]

Do you have a source for the various SHARP sensors the technical binder mentions?

[apache8080]

Originally Posted by Ashwin Adulla

We bagged and tagged our robot with 2 4" Colson wheels acting as our shooter. At CVR, we used 4 4" Colson wheels. At SVR and Champs, we used 2 4" Fairlane wheels with safety wire wrapped around it to stop it from expanding a significant amount past 5000 rpm.

Yes we did use a laser cutter for prototyping with wood and it greatly aided our prototyping process as we were able to quickly CAD and test different variables for our flywheel shooter (pg 13) such as hood angle, pulley ratios, ball traction, and moment of inertia. In addition we did use the laser cutter to test out different intakes and also to cut the hubs for our mechanum wheels.

As for the code, our programming team is performing a code clean and is planning to release it soon.

Why did you guys switch from the Colson wheels to the Fairlane wheels?

[TheModMaster8]

could i get a reply to my question??
It was easy to miss

[Travis Covington]

Originally Posted by TheModMaster8

could i get a reply to my question??
It was easy to miss

We have no plans to release the CAD of the robot but are happy to answer any questions you have.

[bigbeezy]

For the hood, it looks like you milled out a slot/track. Did you just use track rollers from McMaster or something different? How did you insure that the motion was smooth and didn't bind/be too lose and wobble?

For the Nexus 5 you have for vision, did you have to power it off of the robot? If so, did you just power via the USB or someother way?

Thanks for sharing, I (and my team) learn a lot from these.

[roboruler]

Originally Posted by bigbeezy

For the Nexus 5 you have for vision, did you have to power it off of the robot? If so, did you just power via the USB or someother way?

Internal Batteries are allowed for COTS computing devices. They did not open the phone up and remove the battery, instead they just ran a USB cable from the robo-rio to the phones charging/data port.

[bigbeezy]

Originally Posted by roboruler

Internal Batteries are allowed for COTS computing devices. They did not open the phone up and remove the battery, instead they just ran a USB cable from the robo-rio to the phones charging/data port.

Good to know, thanks!

[sanddrag]

Do you guys do your laser cutting in house? Whether it is or not, I'm curious what make and model of laser you use.

[Ashwin Adulla]

Originally Posted by bigbeezy

For the hood, it looks like you milled out a slot/track. Did you just use track rollers from McMaster or something different? How did you insure that the motion was smooth and didn't bind/be too lose and wobble?.

For our hood, we did mill out a slot on both hood plates and used what could best be described as a T-slot roller to move along the slot (I have attached a link of a T-slot roller to better visualize how our sector gear was able to move along the slot). In our case, the T-rollers, two on each side, were made out of plastic and turned down on the lathe. While assembling the hood, we did encounter an issue of the motion being somewhat rough due to the friction as the lateral surface of the T-slot roller contacted the inner surface of the slot. To fix it, we simply took a small file and filed down the lateral surface of the roller in addition to cleaning the slot with isopropyl alcohol (we used the same alcohol on the inside of our hanger weldment to ensure the inner tube would smoothly extend out for hanging). As the sector gear did extend past the halfway point on the slot, a slight wobble was noticeable by virtue of the distance between the bottom of the sector gear and the top of the hood plate shortening. However, this wobble was not deemed to be significant concern affecting our shot.

http://el34world.com/Misc/Cnc/images/Img_7561.jpg

[MrRiedemanJACC]

Originally Posted by Travis Covington

We have no plans to release the CAD of the robot but are happy to answer any questions you have.

I was curious on your climbing gearbox, what gear ratios did you use? Could you explain a bit more about it? Thanks and great document!!!

[weller2811]

im trying to find the same wheels they used but i cant find any that are not extremely expensive on mcmastercarr.

[Cothron Theiss]

Originally Posted by weller2811

im trying to find the same wheels they used but i cant find any that are not extremely expensive on mcmastercarr.

Yup. That's the drawback. They're $30-40 each.

[Cory]

Originally Posted by Cothron Theiss

Yup. That's the drawback. They're $30-40 each.

They are sort of expensive individually but if you think about it, you need 1, maybe 2 per robot, they literally do not wear. They will last until well after you stop using the robot, they are very consistent, and it's the most critical system on your robot for scoring points outside of drive.

When you account for all those factors, $80 is downright cheap IMO.

[Cothron Theiss]

Originally Posted by Cory

They are sort of expensive individually but if you think about it, you need 1, maybe 2 per robot, they literally do not wear. They will last until well after you stop using the robot, they are very consistent, and it's the most critical system on your robot for scoring points outside of drive.

When you account for all those factors, $80 is downright cheap IMO.

Oh I'm think they're an excellent investment, that's for sure. My team kinda balked at the price tag, so I doubt they'll get any, but we'll see. Course, that's still cheaper than waiting until the last minute to buy all of the parts we want and paying for next day shipping.