Identifying sensors as being compatible with Cortex and/or V5?

I couldn’t find a conversation string that is still open on this subject. My apologies as new to the Vex community and have inherited Cortex and V5 gear.

  1. My understanding is that V5 brain has “legacy ports” to accept sensors from Cortex vintage. Is this correct?
  2. I know that the current Vex purchase catalog states if sensors are compatible with Cortex & V5. If I pick up a sensor out of my historical loose supplies, how do I tell if it’s designed for Cortex and/or V5? Is there a different wiring harness/port for the 2 versions?

Thanks in advance!


cortex is 3 wire. red black and white wires. ugly. v5 wires are sleek and black. hot


Thanks - that helps on the ID’ing Cortex vs V5. Are there any Cortex sensors that won’t work with V5 brain (assuming that you have enough legacy ports left to plug-in the sensor)?
P.S. I have figured out that Cortex 393 motors don’t work with V5 (just getting myself up to speed on all things Vex!)

All of the sensors with a smart port (4P4C connector) communicate over RS-485 using a proprietary protocol and are not compatible with the Cortex (or any system other then the V5 for that matter). All of the old 3 wire Cortex sensors will work with the V5 through the 8 3 wire ports or through the external ADI. The 393 motors can work with the V5, just at a reduced power (unless you go through a power expander) but either way, it’s not legal for use in competition.


The integrated encoder modules (integrated motor encoders) for the 393 motors will not work with V5 in any capacity (not that you will have much use for them anyway). They use a 4-wire I2C connection not supported by V5.


Sort of - anything with a 3-wire port (except the speaker) should work with the V5 brain, but there were some other cortex-compatible devices that used different connectors which aren’t present on the V5 brain. These include:

  • LCD
  • Integrated motor encodes for 393 and 269 motors
  • Anything else that uses the cortex’s UART or I2C ports
  • Speaker (uses the same 3-wire connector, but must be connected to the special ‘speaker’ port on the cortex which has a different pinout)

But the functionality of most of these devices is no longer necessary anyway - V5 motors have encoders built-in, the brain has a screen that you can draw to, and the speaker… I know some people miss it, but as a ref, I don’t too much.


Who cares about Bo3. Bring back speakers! :slightly_smiling_face:


Hey, I want to have a color sensor on my competition robot, but I have a V5 brain. I do not want to buy a V5 vision sensor though, since they are very expensive. Is using cortex sensors on a V5 competition robot legal?

yes, they are competition legal and compatible through the 3 pin ports.


Thank you! I couldn’t find that in the rules. Guess I wasn’t looking hard enough.:slight_smile:

There is no Cortex colour sensor though. The V5 Optical Sensor will be coming along soon.

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Oh. Is there something that can be used to identify and sort the balls by color, then? We want to have a sensor like that for autonomous period, and we have a bunch of old cortex stuff, so we don’t want to buy a V5 vision sensor.

For the Vex Change up game, I mean.

If you do some testing you might be able to get a line sensor with a red or blue filter to sense each color of the balls.


Your best bet will be the V5 Optical Sensor when it is released soon, limited details on this page: Coming Soon - VEX Robotics

It is in theory possible using 2 of the old Cortex Light Sensor and some transparent blue plastic as a filter on one, and transparent red plastic as a filter on the other (legal under rule R8 a). You’d also need a light source so the VEX Flashlight could probably be used for that legally, I can’t see that it is prohibited in the Game Manual.
But if you don’t have 2 Light Sensors and a VEX Flashlight already, and don’t want to use the Vision Sensor, it’ll be much better to wait for the new V5 Optical Sensor.