Spin Up Ri24Hr - MARC

Super recommend folks follow that link - you won’t be able to clone their bot cause it’s not Vex - but it goes a long way to explaining why this MARC bot works so well. Great concepts and explanation from a team that clearly put in a boat load of effort designing/testing/iterating their bot for a round-flat-thing shooting game.


I’m so traumatized from the forums that I’m surprised it isn’t a rickroll.


what motor speed did you guys manage to get the motors operating at? right now i cant seem to get mine working at over 350. any tips or tricks? i have bearing flats and everything.

You could memorize the link to the common rickroll. This shows up in my bottom left corner when I hover:
Screenshot 2022-05-29 5.34.51 PM

1 Like

Isn’t the main rick roll link the one that ends in XcQ

When I tested the flywheel with one motor it did have the power necessary to reach the desired speed.

So then why did you go with two? Was it more consistent?

It’s a ~1/16" sheet of abs with anti-slip mat ziptied to it to make sure the discs are spinning at similar rates as they come out of the shooter.

This is actually the first iteration of the intakes, we went through slowly and added each roller section and tested them to make sure it worked properly and didn’t mess up the previous sections before moving to the next one.
Then once they were all together, we tested them with motors running and used abs, standoffs, and zipties to fill in any trouble spots where the discs wanted to sneak out / jammed up.

We had 4 motors for the intake/shooter, so we evenly split them between the 2 subsystems to make sure that we had the torque to overcome any issues with the intake feeding, and have low enough recovery time after a shot to fire all 3 discs in quick succession.
You could make a functional flywheel with only 1 motor, but I think I’d want atleast 2 on it to be able to fire at a faster rate.


Does anyone know the angle or curve dimensions of the plexy that makes up the shooter?

1 Like

Welcome to the forum…

  • how about doing some of your own research and design, rather than trying to make an exact copy of someone else’s work.
  • It’s a bad habit to call clear plastic “plexy”, since Plexiglass, a trade name for PMMA or Acrylic, is specifically called out as an illegal plastic in the game manual.

It is funny when you get the Vex elitists in the forum.


Just figure it out by yourself. If you want step by step instructions, you may as well just build the hero bot.


Wow. That’s one take, and I completely disagree.

Here’s one thing to consider, where many of us who do engineering for a living (or maybe have retired from it) that come to this forum to help provide guidance, insight, and experience come from.

What @kmmohn is getting at here in regards to the correction on “plexy” is something that’s as important to engineering as it is science, medicine, and lots of other technical fields, and that is that jargon can lead to confusion, slow down communication, and in its worst cases cause harm or death. By taking the time to use the proper, common name for something, you’re communicating that you’re speaking about a commonly understood thing, and that takes away from having to have extraneous conversations (like this post) just to get to common ground.

Track change, but in the same common thread, you learn best by working to gain your own understanding. No good mentor/senior person should take you to task by asking informed questions about a topic, but a good mentor should not just give you the information, as you’ll learn nothing from it except to look for that next shortcut. And guess what real-world implications shortcuts have when it comes to real-world engineering? At its worst, harm to people and death.

So, take that attitude, examine it, and decide if you’re really looking for help and learning, or if you’re just looking to be a needy snark.


I have a question how do you use piston indexer and piston angle actuator? I have no idea how to working. If you have any link to explain how to use and please send me link. Thanks!

Honestly it’s pretty simple to understand from the reveal. The indexer indexes the discs, holding them in place until the flywheel gets up to speed. The angle adjuster increases the angle the discs are shot at, which can create many advantages strategy wise.

Why did you use a spiral flywheel disc mech instead of a straight one? Are there any benefits?

The reason teams might do this is that it allows the disk to contact the flywheel for more time. In a curved design, the disk will ride along with the flywheel and then be shot out. A straight shot system would have the disk contacting the flywheel for a brief moment. Because the curved design had the disk contacting the flywheel for longer, the disk will pick up more energy from the flywheel.


Mark Rober copied you

E: Realized this was already posted in Dankest Memes, but who cares


aint no way you’re getting more than 25 rings in each goal

They’re called discs this year. Not rings. That was last year’s game. Also, have you tried putting more than 25 discs in the goals? I don’t have access to a field quite yet.