[Ri3D] BOOM DONE. We're not done...

[wilsonmw04]

about the camera:
Are you using the driver station to process the images? If so, how are you dealing with the bandwidth limit?

[Joe Johnson]

Originally Posted by wilsonmw04

about the camera:
Are you using the driver station to process the images? If so, how are you dealing with the bandwidth limit?

I have heard mixed reports with respect to bandwidth affecting processing on the driver station. Sorting through it all, I believe that this is no longer a major issue.

BUT, even if it IS an issue, the HOT or NOT call is an application where we will have time to make a decision. We have odometry from the wheel plus range finding via sonar to get our distance right (and detect a blocker in front of us -- which we can avoid using our gryo-stabilized omni-motion provided by our mecanum wheels -- have I told you how much i LOVE the feature set we put together on this robot ;-)

Joe J.

[wilsonmw04]

Dr. Joe,
Thanks for spending the time answering all these questions. I have on more: what us your current weight of the robot as it stands right now?

[Joe Johnson]

Originally Posted by wilsonmw04

Dr. Joe,
Thanks for spending the time answering all these questions. I have on more: what us your current weight of the robot as it stands right now?

109 lbs WITH the battery & bumper so we are 40-50 lbs under the limit.

Oh a clarification. Someone asked on Twitter if the bumpers were removable. Yes, the are (or would be if we had guarded the pop rivet gun from Nate -- we'll have to drill out the one rivet he got off before I smacked him upside the head -- we were almost all rookies on the team after all ;-)

Joe J.

[pilum40]

Dr. Joe:
I'm the coach for Team 3355 in Arlington, Texas. My team is frankly open mouthed about Boom Done. We did have a couple of questions please...for now...
1. When you use "green cord" in your shooter", what kind of cord do you use? Did you custom make the pulley for this cord or is it off the shelf?
2. What was the gauge of wire you used for your catapult/shooter? Did you hand form it or have it made?
3. What was the material you used for the "Toro Horns" please? We have a running bet (lunch) that it was rough sports tape or something similar. Please let us know, we're all hungry!!

Thanks in advance!

Steve Miller-Coach
The Purple Vipers

[Sean Raia]

I am still in awe as to how you guys pulled this off. This robot looks like it can compete with the best of them.

I really like the acquiring system and the consistent catapult. And Im baffled at the amount of electronic features this robot has built into it.

A sure winner of the Ri3D lot if you ask me.

[Joe Johnson]

Originally Posted by pilum40

Dr. Joe:
I'm the coach for Team 3355 in Arlington, Texas. My team is frankly open mouthed about Boom Done. We did have a couple of questions please...for now...
1. When you use "green cord" in your shooter", what kind of cord do you use? Did you custom make the pulley for this cord or is it off the shelf?
2. What was the gauge of wire you used for your catapult/shooter? Did you hand form it or have it made?
3. What was the material you used for the "Toro Horns" please? We have a running bet (lunch) that it was rough sports tape or something similar. Please let us know, we're all hungry!!

Thanks in advance!

Steve Miller-Coach
The Purple Vipers

Green Cord. It is the metric size solid core urethane round belt on this page from McMaster I use a ton of the 6mm (8112K33), but the 4mm stuff is also great. Run it around the pulleys to get a free length, cut the belt 3-6% short, use a lighter to melt the end (act like you are making a golden brown marshmallow), press together the ends, hold til cool, trim the joint with a side cutter. It is a REALLY useful way to spin something at a distance.

Pulleys are laser cut acrylic 1/8th thick. We cut a ton of these with a "FIRST standard" bolt hole pattern 1/2" increments. We then can stack up plates to make pulleys. These are not just good for actual robots but especial for prototyping.

Loop Gauge of wire is 1/4" steel. We had it laying around the shop.

Toro Horns. You are not going to believe it: Schedule 80 PVC (thicker wall than Schedule 40). I heated up some 1/2" hex shaft and melted it in place so that a Versaplanetary shaft fits tight inside.

Dr. Joe


* which roughly stated is (6) #10 holes on a 1.875" bolt circle with a 1.125" center hole.

[Ernst]

Does Ri3D give an "Innovation in Control" award? If so, you nailed it.

[AllenGregoryIV]

Great job, I love how you all managed to innovate in such a short amount of time.

What was the final gear ratio for shooter?

[Henrique Schmit]

Bravo, my new favorite RI3D team, i'd not be surprised to see this robot in the championship finals.
I really loved that bumper idea and you really innovated with the control stuff and sensors. Are you going to post the cad models and code you used? Where?

[Joe Johnson]

Originally Posted by AllenGregoryIV

Great job, I love how you all managed to innovate in such a short amount of time.

What was the final gear ratio for shooter?

Working on a spec page but 15:1 is the short answer.

[Shmuel]

Originally Posted by Joe Johnson

15:1

Is that gear ratio including the sprocket, or just the gear box?
Also thank you for what you are doing, your robot is really amazing.

[ekapalka]

Originally Posted by Joe Johnson

Working on a spec page but 15:1 is the short answer.

Please excuse my lack of intelligence, but aside from using the Green Cord to spare your motors, what stopped you from simply using AndyMark gearboxes with that or a similar reduction (like a pair of 8.75:1 toughboxes with reduces by 2:1 on the output)? Is there some other mechanical advantage to using the gigantic sprockets? Thanks!

[Joe Johnson]

Originally Posted by ekapalka

Please excuse my lack of intelligence, but aside from using the Green Cord to spare your motors, what stopped you from simply using AndyMark gearboxes with that or a similar reduction (like a pair of 8.75:1 toughboxes with reduces by 2:1 on the output)? Is there some other mechanical advantage to using the gigantic sprockets? Thanks!

I was scared of the impact loads we were going to put into the arm. So, I worried about going with a "live axle" where we transmit the torque to the arm via a hex shaft (or worse, a 1/2" round with a single key).

So... ...we went with a larget sprocket on the last stage because then we get to transfer the torque to the arm out at a nice (6" in our case) radius. Also, we have all those teeth engaged rather than just a tooth or two.

We went with the green cord on the first stage because it is springy and it can slip. This lets the energy in the armatures go someplace other than into breaking gear teeth and/or snapping chain.

COULD we make a Toughbox work? Maybe yes. But, we made the thing we had work so, I have an existence proof the system with chain and green cord working. I like that the loads are lower and the energy has someplace to go. So... ...unless I had a compelling reason to go another way, I wouldn't change.

Dr. Joe

[Team1339]

We are going to be using the 7 segment display and the rangefinder and we wanted to know how you mounted them.

Thank you!