The Confusing Legality of Additional Microcontrollers Based on \<R12> and \<VUR12>

Are you allowed to have additional microcontrollers, computers, and third-party sensors on your robot? The game manual doesn’t seem to be very clear on this subject, and I couldn’t really find anything about it in the High Stakes Q&A as of today. Rules <R9>, <R12>, and <VUR12> in version 2.1 of the High Stakes game manual muddle the waters on this subject.

<R12> seems to make all additional microcontrollers illegal, no matter the application.

<R12> Robots have one Brain. Robots must ONLY use one (1) VEX V5 Robot Brain (276-4810). Any other microcontrollers or processing devices are not allowed, even as non-functional decorations.
… This also includes devices that are unrelated to VEX, such as Raspberry Pi or Arduino devices

However, <R9b> and <VUR12> seems to be in direct conflict with that statement.

<R9> discusses non-functional decorations, and <R9b> provides a specific example.

b. Small cameras are permitted as non-functional decorations, provided that any transmitting functions or wireless communications are disabled. Unusually large cameras being used as ballast are not permitted.

If it is a digital camera, it would almost certainly have a microcontroller within it.

Additionally, <VUR12> allows for “sensors and Additional Electronics,” seemingly including additional microcontrollers for “processing”.

<VUR12> There is no restriction on sensors and other Additional Electronics that Robots may use for sensing and processing, except as follows:
a. Sensors and Additional Electronics MUST be connected to the V5 Robot Brain via any of the externally accessible ports (i.e., without any modification to the microcontroller). A sensor may be connected to a processing unit which then connects to the V5 Robot Brain

Both of these rules seem to be contrary to <R12>. Am I missing something? Which rule should take precedence?

These conflicting statements lead me to these questions:

  1. Are addressable LEDs legal? WS2812 Neopixels, and other addressable LEDs like DotStars have microcontrollers/special LED drivers within each device to actually interpret their respective protocols. Although the microcontrollers within addressable LEDs are extremely limited in their functional scope, they still seem to be considered microcontrollers. Furthermore, would it be legal to have a separate microcontroller in between the addressable LEDs and the V5 Brain to handle the bitbanging/protocol? The brain could just send simple on/off commands to the intermediary microcontroller, seemingly acting as a piece of “additional electronics” as outlined in <VUR12>.

  2. Would a sensor like the PMW3901 Optical Flow Sensor, a sensor (a small camera) with a built-in microprocessor performing the optical flow logic, be legal? A further edge case could be building your own sensor. Hypothetically, you could put together a camera, and a microcontroller to create an optical flow sensor for odometry. There is a separate microcontroller performing processing tasks, but could be considered part of the sensor.

Both scenarios seem to be legal based on <VUR12>, but also seem to be outlawed by <R12>.

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as clarified in the manual, VUR stands for Vex U, which is the collegiate level of VRC, assuming your a V5RC competitor, these rules wouldn’t apply and you should follow R12

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I realize now that <VUR12> only applies to VexU, however I’m still curious about the legality of addressable LEDs in V5RC, since I have heard of other teams using them in past seasons.

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This is legal, as long as they are controlled by the V5 brain. Quite a few topics about this

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Addressable LEDs have historically been made legal by Q&A, and are allowed to even give driver feedback by rule R12.g. While R12 does state no external processing devices, the rule tends to be enforced as closer to no programmable microcontrollers, as I’ve been allowed to use this custom speaker, which while uses no microcontrollers, definitely is a processing device. This was allowed by the GDC during worlds inspection during spin up, but again, this isn’t a written ruling, so it would be up to inspector discretion at any events today.

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Thank you and everyone else for the quick responses!

Regarding Cooper_614A’s response,
That makes sense, although <R12g> doesn’t exist in version 2.1 of the High Stakes game manual. Which version of the manual is <R12g> in?
<R12> in the current manual seems to be pretty cut and dry regarding other microcontrollers, but as you mentioned, historical precedent would make it seem like devices like addressable LEDs are legal. Do you think this merits a Q&A post?

Sorry, that was a typo, I meant to say R9.g.