Smart port wiring diagram?

I’d like to hook a 3-wire servo up to the 6-wire Vex IQ smart port. Is there a direct 1-to-1 mapping of wires for the servo to the smart port? If so, what wires? Or is it not that easy?

This won’t be directly possible, as the 3-wire servo motors are looking for a servo-based timing pulse (18ms PWM-style pulse), whereas the VEX IQ ports are all I2C digital ports sending out bytes to devices with microprocessors attached (or in the case of the touch bumper, simply reading voltage across two analog pins and an ADC). I think you may (currently) be stuck using the VEX IQ motors with the VEX IQ brain.

Thanks for the info. I was not expecting the VEX microcontroller to not have any PWM I/O. That was completely unexpected. Is the wiring and VEX IQs I2C protocol documented somewhere so a person could take a small Arduino to hook it up run the PWM?

It is not publicly documented. You would have to contact VEX Support regarding any more information about it or maybe Art will respond to this post (although maybe not this week since it is VEX Worlds and just about everyone is in California)


We’re looking to provide full documentation of the VEX IQ sensor interface (it has I2C, analog, and digital lines) along with the wiring diagram soon to allow users to interface their own sensors and devices.

We’ve been a bit busy lately preparing for the VEX World Championship Event, so we apologize for the delay. If you have any additional questions, please email As Tim already mentioned, many VEX staff members will be at the VEX World Championship Event this week. If you are there we would be glad to help you with any additional questions or comments you many have in person.


  • Art

Wow, the VEX IQ sensor interface would be awesome! I’d love to connect via I2C to a VEX Cortex, or to an Arduino DUE or another I2C device.

Where will this information be posted when it is available?

Is the documentation available now?

Hi pauljurczak,

James Pearman has provided documentation and code examples for how to interface custom sensors to the VEX IQ control system here:


  • Art