Power in 3 wire ports

Ok so I use VEXCode and I have LED Lights on my robot and they turn on when they plug in. I want a button to essentially have power stop running to the port therefor turning the lights off and I want to be able to turn them on again. Any ideas?

If you are having code that would turn the lights on and off, by definition, you will be turning your LED lights into a 3rd party sensor which is not legal in VRC. Don’t change anything. :slight_smile:


Damn really the more you know I guess.

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Hi Connor, can you walk us down the path to get that the LED’s become a 3rd party sensor?

@Caleb_9821E - You can drive the LED off the three wire port using the motor controller, you need to remember that there isn’t very much current available for them. If you are looking for a way to signal out to the drive team that something is going on with the robot (cube capture), you should look at these (https://www.vexrobotics.com/276-2176.html) they are LED that plug into the 3 wire port. You can use 3 wire extension cables to move them to a visible location.

In Nothing but Net one of my teams used LED’s to show that the flywheel was up to speed and ready to shoot. Solid red was stopped, flashing red was not ready, green was fire away. YMMV.


I would like to provide this image for reference (If your LED strip has 2 pin connection soldered onto them):

To use the LED’s without sensors or programming,

connect the LED’s into the red and black wires of the 3 wire pin.

In order to turn the LED into a sensor,

you will need to connect the light’s pins into the red and white wires of a 3 wire pin.
If I am not mistaken, your brain should see the LED strips as an LED indicator, which you can program in vexcode by adding the 3-Wire device “LED”.

Then, you can program it with:

LED.on(); //Turns on LED
LED.off(); //Turns off LED

I am not sure about how much voltage will be applied to the LED’s to get full power, so if you don’t have enough voltage I would suggest the possibility above which you can find further information by reading this post and below in the thread linked:


This is an interesting use of the term “sensor”. What is being sensed by the LEDs?

Absent any further guidance (such as a relevant Q&A entry), I would not describe robot-controlled LEDs as a “sensor”, and would likely rule them a non-functional decoration provided no other rules are violated (e.g., the lights aren’t designed to mimic game objects or otherwise interfere with opponent robots)


Although this was 1-2 years ago:

A VEX Speaker emits, yet does not sense, but it is still considered a custom sensor by the GDC’s standards if they receive a command within robot’s program. LED strips emit, and they don’t sense, so we can likely use the VEX 3rd party speaker rule as a projection of what is to be expected if it were ruled this year.

So when I was meaning “by definition,” I was meaning the definitions that the GDC placed on specific items within the past. These can be re-clarified, of course, but unless they are re-clarified my common sense would result to previous rulings within previous years.

Hmm, that’s not how I interpreted that Q&A entry. The original question asked about a VEXU team using a non-vex speaker as a “component of a custom VexU sensor”. Likewise, the question linked from that question asked about using LEDs as a component of a custom sensor in VEXU.

OP, on the other hand, wants to add LEDs to their robot as a decoration, not as a part of a custom sensor (custom sensors aren’t legal in VRC anyway). Adding LED strips as decorations to robots is a fairly common thing to do, and has been ruled legal in various Q&A entries. As far as I am aware, there are no rules or Q&A entries prohibiting driving non-functional decoration LEDs from the robot brain.

(of course, if you are controlling the appearance of the non-VEX LEDs to provide feedback to the driver about the status of the robot, then your LEDs are no longer a non-functional decoration and thus illegal)


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