Cortex Should be Legal

This past weekend as a Head Referee, I had to do something I never want to have to do again; I had to send 2 teams home before the competition started. What was their offense?
Was it a G1 violation? No.
Was it a G6 violation? Nope.
No, their only offense was using the cortex control system.

The cortex control system is still fully compatible with the field electronics. It would have been trivial to inspect them and to allow them to compete anyways. In no way would they have had an unfair advantage.

It was not my choice to remove the teams from the event, nor the EP’s. Our regional RECF representative (who is amazing and deserves no blame whatsoever for this) contacted his superiors, and was told that they could not compete because of the rules this year from the GDC.

The RECF’s Mission statement has been talked about lately here on the forum. I’ve quoted it in full below:

The Robotics Education & Competition (REC) Foundation’s mission is to increase student interest and involvement in science, technology, engineering, and mathematics (STEM) by engaging students in hands-on, affordable, and sustainable robotics engineering programs.

To @Grant_Cox and the rest of the GDC, I ask this:
How does the ban of cortex this season further the RECF’s mission to engage students in a hands-on, affordable, and sustainable robotics program? How were the students that were sent home made more interested in STEM?

The Game manual (written by the GDC) describes VRC as “an opportunity to hone the life-long
skills that will characterize the problem-solving leaders of tomorrow.”

Why does the GDC deny that opportunity to teams using the cortex hardware?

V5 has been out of stock for a majority of the season thus far. Even if the teams had the funding to upgrade to V5 (which I am not sure of), they could not have, because kits are not even available for purchase. The GDC has had numerous opportunities this season to recognize the V5 supply difficulties and to make cortex legal again, yet they have chosen not to.

I volunteer my time at VRC events because I, as a long time competitor (8 years), appreciate the positive inspiration VRC has had on my life and on my decision to pursue a career in Software Engineering, and I want to participate in bringing that inspiration to new teams. What happened this past weekend has me questioning why I am doing this. These teams were discouraged, not inspired. These students were not allowed the opportunity to run the robots they had designed, built, and programmed, and to be inspired by their experience at the competition.

The season is not yet over, the GDC still has the opportunity to make cortex legal and to give more students the opportunity to be inspired by the Vex Robotics Competition.


I was told by my mentor that it is because no more updates are going to be sent to the cortex, and parts are not going to be produced, I don’t know if this is the cause of the change, or the result of the change, but it was obvious from the start that they were going to change it to only V5 one season. I’m just surprised that had cortex lasted that long.

Discontinuing the product line and no longer supporting it is one thing. V5 is the current generation, so of course they’re going to be putting development time into that. But it’s just cruel to have a team show up with a robot they’ve worked hard on and have to tell them “sorry, the cortex is no longer legal, you can’t compete, you have to go home now, bye.” Especially given this might be their only competition of the season.

The response should have been “just so you know, this product line is no longer legal. We’re going to allow an exception today, contact this person at the RECF and make sure to get a V5 brain.” Nobody is using a Cortex to gain a competitive advantage over the V5 motors…


I was also volunteering at this event, and personally I was quite disappointed that the teams in question were forced to leave. The kids spent time on their robots, and they would have gotten a lot out of being able to compete. Letting a cortex team play harms no one, but forcing them to leave absolutely does.


I’d like to add something for context. For those of you too young to remember, before the Cortex was the PIC. The Cortex was released in the 2010-2011 season (Round Up) and the PIC remained competition legal all the way through the 2017-2018 In The Zone season.

EDIT: I have been informed I am incorrect. It was actually seemingly legal through the 2019-2020 Tower Takeover season. PIC, Cortex, and V5 were all legal in that season.


Disappointing; I’m fairly certain I remember @Grant_Cox mentioning specifically in the recent Town Hall that hard-ship exemptions would be considered, though the scenario mentioned on the call seemed extreme (team in Africa with no V5s for 500 miles).

Would be a great opportunity for the community to reach out and share spare components. I’d be willing to share a battery, controller and radio to each team. Looks like there are only a handful of remaining competitions in Arizona; would be nice if they were able to become “legal” to get into one…


I believe they were a middle school team and our middle school state championship has more capacity than there are middle school teams in the state, so if we can get them a V5, they should be able to compete.


DM me details of where to ship. I’m hoping others will be similarly inspired so that 2 brains and at least a few motors find their way to the teams.


It is such a sad story and broke my heart. I remember when I was a volunteer at World I saw teams with limited supplies and had to reuse anything they can find. I also saw teams with luxury tools. In my region, I saw schools with limited space and students working on small tables and no chairs. I also saw a school with a spacious robotic lab. I am not sure if REC and VEX make a profit by selling V5 or how much they made. However, allowing the teams with Cortex to compete has every benefit for the teams and the community. It is a good opportunity to teach kids rules and exceptions, order and love.


As Mr Rogers would say, “Look for the helpers”. Sometimes there are thoughtless decisions that are made. That gives an opportunity for the community to step up.


couldn’t agree more, I see no benefits to banning the system outright, even though it’s discontinued. Especially this season where many teams can’t get v5 components even if they had the money to, which is even more of an if considering the price increase on v5 components.


I have freely offered gear as many others have - so no lack of helpers. What I am confused about is how did the middle school team end up in this situation? are they an independent team that bought VEX gear on eBay? What was the experience of their adult coach? Hard to see where the no Cortex messaging got lost?

As forgiving as we might want to be “give that team a pass”. How is that fair to all the other teams that did not present themselves with a Cortex based robot? I think what would have been a cool thing to do at that event would be to have pickup matches on the practice field - good practice for teams and positive experience for the middle school cortex teams (play 2 cortex v 1 v5 format :slight_smile: ). Not everything has to be play qualifying matches to achieve that learning opportunity. Another option is invite team members to shadow some of the other teams, be part of pit crew (yes I have see that done with teams that a number of their teammates were unable to come to event.)

This season has been rough in every way possible but I do like how teams help one another out. For my upcoming event, last chance for teams to advance to regionals - one organization withdrew their teams to support those teams that could not compete at all due to Covid and snow cancellations. Class acts everywhere.


PIC wasn’t really legal in the 2019-2020 season. They gave you examples of legal control systems in tower takeover, as well only the VEXNet 2.0 key being legal, which was only compatible with the Cortex.

That said, Cortex didn’t have nearly the supply chain issues that the V5 has now.

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Obviously this isn’t the point of this thread (and I think the fact that it was unambiguously mentioned as legal through 2017-2018 proves my point about how much more generous they were with the PIC grace period) but it does seem that it was still technically legal?

r. Robots must use ONLY one (1) VEX EDR Microcontroller.
a. Examples of VEX EDR Microcontrollers are the VEX ARM® Cortex®-based Microcontroller (276-2194) and the V5 Robot Brain (276-4810).

The fact that those are listed as examples and not an exclusive list, as well as the explicit mention of PIC in a list of things allowed

A VEXnet upgraded 75MHz Transmitter may only be used in conjunction with a PIC Microcontroller

seems to imply it was competition legal.

Again, not remotely the point of the thread, I just really want to believe there was a season where PIC, Cortex, and V5 were all legal.

EDIT: and I just saw the rules below that with Cortex and V5 as an exclusive list of valid options. OK, seems like it wasn’t legal and the rules were just weirdly written that season.


PIC was legal during 2019-2020. The rules start tightening around R16 which prohibited the 75MHz crystal radios, but events could allow said radios at their discretion under R31.

The PIC did actually have a VEXNet upgrade. From what I've heard it's pretty rare though (hence the rule about no mixing PIC and newer controller)

Going back on topic, I think they should’ve just done the same thing as 2019-2020. That is, allowing the older cortex at the event’s discretion.

EDIT: Point in case, PIC was allowed to compete on paper even though it was way past EOL, unlike with the EDR cortex and V5.

Even though the software was depreciated, even though the VEXNet 1.0 radios were problematic, even though the hardware wasn’t worlds legal, at the very least PIC was still technically allowed to compete at events under the rulebook.

I’m honestly surprised RECF would force all teams to use V5 after VUR4 during 2018-2019.


I have to agree - there were many lost opportunities here to turn a potentially negative situation into a positive. It’s easy to paint the RECF as the big-bad in this situation, but a little non-linear thinking by others could have gone a long way here.


I agree that RECF should have made and accommodation when it became apparent in 2020 there were going to be V5 supply issues. There are teams in Delmarva that are not competing since the didn’t have access to V5 hardware.

I’m not sure how they got through the build season without reading the rules. They are pretty clear about only having V5 hardware. But getting teams to read the rules is hard.

While I’ve committed my share of event atrocities and have invoked the ire of RECF, I don’t know if I would have let them play. I’m sure I would have gotten an earful from teams that lost matches being paired with the Cortex teams. I’m all about the experience and inspiring teams, this is a tough line to cross.

In hindsight, this is something that should have been discussed back in October. And maybe it should be on the table for the 2022-23 game. I don’t have insight into the VEX supply chain. I do know that supplies of components are just a huge mess. Try to get a Raspberry Pi with 8 GB is almost impossible. They are predicting it will be 1Q 2023 before they will catch up with the current demand. But if lots of teams are not going to be able to get V5 electronics as a stand alone pack, maybe a 1/2 step back to allow Cortex makes sense.

About the PIC backpacks, I have/had 4 of them, they were pretty cool. So as I read the rules, they would have been legal under the “need VEXnet” rule. TBH, those whip antennas on the 75Mhz transmitters scared the daylight out of me. More than once I’ve been wacked in the face.


I completely agree with everything that’s been said above, and here’s my standpoint on the issue:

So, I go to a STEM magnet school, where our only ‘sport’ is robotics. Because of that, robotics is a massive deal here. We’re a combined MS/HS, and because of that, we have to allocate our funds between the two coexisting orgs(4591 & 3249). As far as funding goes, we’re treated like a club, not a sport. So we don’t really have all that much.

We had enough kits between us to have as low as 2-3 person teams, which I feel is the perfect number for some new students learning robotics. So when I read that section in the manual in June, I was worried. Worried that the opportunity to compete in this wonderful sport I’ve come to love would be ripped away from those who might not get as much grant money as they need. As of right now, my club has forced us to be in teams of 4-5 people, and is putting all extra expenses towards new kits, instead of registration for more comps to give them more chances of doing well(Backstory on that, we get 1-2 comps a year, 3 if we’re lucky. If we could go to more comps, we’d have more teams do well, advance, etc.).

However, we still have all of our old Cortex hardware locked in a closet in our parts room. If we had a setup similar to 2018-19, where the middle school teams used Cortex, and high school teams used V5, then everyone would, in theory, have equitable access to everything they’d need to compete. It truly saddens me that our club has come to this.

Honestly, I fully understand where the RECF is coming from with this, however much I dislike it. Think of VRC like a new gaming console. Hardware is a particular game. The company that makes that console isn’t going to update the software forever so you’ll be able to play the game, thereby forcing you to pay for a copy of the game, or a different game entirely, that will run on the console.

I’ve been speculating about this quite a bit recently, even to the point of putting together a pitch to my school board about it. Banning Cortex effectively puts a paywall on robotics. The goal of Vex, as stated in the RECF’s mission statement, is “to increase student interest and involvement in science, technology, engineering, and mathematics”, but how can they increase student involvement when those students have to pay to play, and aren’t able to?


This doesn’t make much sense from the RECF’s point of view, actually. If a team has the means to buy V5, they will do so in order to be competitive. Not doing so puts you at such a huge disadvantage any team that has it within their means to get a V5 will. Any team that can’t afford or source a V5 and is forced to play with Cortex hardware will not be any more able to buy a V5 if it is required than if it isn’t. If anything, not requiring V5 would result in more income for the RECF, because a Cortex team might register to compete that otherwise couldn’t.


It’s understandable that cortex will have to be obsolete sooner or later. Eventually, field control or something else of that nature will likely change in such a way that cortex physically cannot connect. But that hasn’t happened yet, and I don’t expect it to for some time. And I don’t think cortex should have been made illegal until it’s incompatible with tournaments. Especially not during a season where it’s extremely difficult to acquire v5 components, affordable or not. It doesn’t seem beneficial to anyone involved for this to have happened.