Answered: Vexnet Wireless Controller Communication problems!

When operating our new robot in wireless control mode, it works perfectly until we make a quick movement and/or reverse the motors. At this point, we loose communication with the Cortex for several seconds.

Is this a know problem or are we doing something wrong? :confused:

Team Zooluk

No, not a know problem. Exactly what do you see on the LED indicators? Does it work all the time when Tethered?


Thanks for quick answer… After some playing around, I figured out that the Cortex battery was low. When I used it tethered and had the joystick power turned on, it worked perfect. With the joystick tethered and the joystick power turned off, the robot “lost connection”. What appeared to be a lost connection, was probably just the battery too low and with the joystick powered on, the Cortex must get some relief from the joystick power? I think the “jerky” movements triggering this was really just a large current surge to the motors quickly reducing the voltage left for the cortex…

Anyway… New cortex batteries and everything works good! :slight_smile:

Another question related to programming:

I downloaded a program and now I cannot control with the joystick. Is there some introductory documentation on how to remove downloaded programs and/or control with just the program or the joystick or both at the same time. I cannot find anything on this.


**You are correct, if the voltage on the CORTEX gets too low it will draw current from the Joystick – the same hold true in the reverse direction. Glad you figured this one out.

If you downloaded an Autonomous only program, the data from the Joystick will be ignored. The only way to change a User Program is just to download another program. If you need to get back to “square one”, just download the Default Code to restore the CORTEX back to an “out of box” state.**

Thank you very much Ricky!!


Your welcome, glad I was able to help…

One more question Ricky-

So it is possible to control the robot with the joystick and a program (at the same time) but I assume the program than has to have code written for the joystick control?

In other words, you can use the joystick only or autonomous only pretty easily but I assume doing both at the same time has a learning curve on the code writing.

I cannot find anything that talks about this or gives examples…


An example using easyC - If you select a Standalone Project and write code that is under an “Autonomous Only Project”, the Joystick can not be used. If you select a Joystick Project, the Joystick can be used. You can now write code that will respond to joystick data and your own code or subroutines. Your subroutines can be controlled from the joystick data – you push a button on the joystick and code that you have written makes the robot spin in a circle for 5 seconds regardless of all the other joystick data.