Cortex/Joystick constantly resetting?

Hey all

I finally have my robot put back together, and it seems to be doing something I’ve never encountered before.

The cortex/joystick seems to turn off / reset itself when I push the joystick forward / reverse to move the robot. Code has never been altered once it was working.

The lighting sequence on the cortex goes like this:

Idle state:

Robot light: Red
Vexnet: Green
Game light: Off

Joystick used:

Robot light: Red
Vexnet: Red
Gamelight: Red

Then it resets itself.

Any idea what may be happening? The robot has run fine before this without any issues.

Thanks in advance.

Any chance the motors were not connected correctly? Do motors other than the drive motors work? It feels like something may be shorted and reseting the cortex. Is the battery good/charged?

Yes, that usually happens to us when our joystick batteries are very low. I would try swapping those out with a fresh set.

If you need another vote – here it is: it’s your joystick batteries.

Thanks for the responses, but could it be the joystick if I am running it via USB A-A thether?

edit- just took a multimeter to each battery and they all check out fine at 1.61~ V.

I will double check motor connections. I hope this is the cause, because I am stumped.

Is it possible your USB A-A cable is bad? This is really a puzzlement. O_o

That could be a possibility.

When the cortex is turned on, and the joystick is on (using vexnet) the robot light is blinking a steady red.

According to the cortex user guide

it seems like the diagnosis would be Fault: User Microprocessor Issue

Is my cortex dead? :eek:

Probably not.

You need to gradually eliminate all other possible problems before concluding that.

  1. Do you have a good/charged 7.2V battery on the cortex.
  2. Hook up the joystick to the PC using the orange serial cable, I seem to remember you were using EasyC, go to the download window and do a “vex system info” and verify that you see cortex firmware and joystick firmware versions (probably 3.16 or 3.17 depending on which EasyC you have).
  3. Are the battery voltages good, if the joystick is being powered over the USB A-A cable then it will read around 4.8v, if from the internal batteries then perhaps 7v or above. The cortex should be 7.2v or above.
  4. If all is OK then create a simple program, one analog joystick to one motor and download to the cortex, does the download work? Can you control one motor.

Get back to us with these results and we can determine the next step.

I’ve done everything but 4, but I’m doing this now.

-edit- ok wrote some code and tested it, but the micro controller robot light still blinks red. I am getting all green on the joystick now though.

Sounds like you went USB to the joystick, I mean use a programming setup like this (but with the USB A-A cable instead of VEXnet keys if that’s easier).

When all else fails,
use the IFI Vexnet Firmware update to reflash the joystick and the cortex,
then reload your code.

If Firmware won’t load, try the paper-clip of death in the reset button holes.

so, reflashed the master code, and all is well again… :confused:

thanks to all who responded.

Do you know whether previous code installed was rev2.x or the current update rev 3.x?

I believed it’s just your joystick batteries being low. This happens a lot for me back when I used to program my VEX robot. Usually if your robot battery or joystick batteries are low, the connection would reset but it is the joystick batteries that would cause the Robot, Game, and Joystick LEDs to light up solid red.

On a rare occasion, it could be the fact your master code is outdated. But if it worked before, then why would not work afterward? If you already reset your joystick, follow the instruction to updating the master code, recalibrating the controller, and establishing a connection with the robot.