Broken? Joystick

VEX V5 Technical Support
#1

I got my VEX kit a few days ago and after charging the robot batteries and joystick batteries, I followed the procedure of connecting the cortex and joystick. Following that, I wrote some code to run a motor when I hit 8U on the controller. The motor was on port 2 with a motor controller 29. When I hit 8U, the motor was running but was jittering. Thinking the motor was bad, I tried a different one. Same problem. Changed motor controller. Same problem. Tried a different port. Same problem. Tried different buttons on different channels. Same problem. Used a USB A-A Tether cord instead of VEXnet Keys. Same problem. Tried different code using a button to trigger the motor. No jittering.

I think this is a joystick problem. I’ve flashed the master code of the cortex and joystick five times, flashed the robotc firmware 15 times, and recalibrated the joystick so many times, I don’t remember.

If my joystick needs to be replaced, will it cost me anything? I just paid $1,500 for this.

Thanks,
SamThe(Disappointed)

#2

If you post your code it will help us check if there is an issue with that (to me this sounds like a code issue) . Your kit should come with a 90 day warranty on all the electronics so if it is indeed a fault with the joystick you can contact @VEX Support for a replacement or repair.

#3

task main()
{
while (1==1)
{
motor[mainMotor] = vexRT[Ch6];
if (vexRT[Btn6U] == 1)
{
motor[mainMotor] = 127;
}
else if (vexRT[Btn6D] == 1)
{
motor[mainMotor] = -127;
}
else
{
motor[mainMotor] = 0;
}
}
}

#4

@SamTheGreat

This is the problem I believe. There is no Ch6, so I don’t know what the cortex will do about that, but if it sees it as a joystick sending a 0, the code will constantly switch from sending that 0 and the ±127 on Btn6U/D

#5

But i’ve also tried all of the other channels. Including 2, 3 and 8. I still get the same problem.

#6

Just delete that line of code. It’s not needed with your if statements updating the motor.

#7

Ok, I’ll be sure to try that… I’ll get back to you in a few days.

#8

No matter what channel you use you will get the same problem. What is happening is when you press the button it tells the motor to go at +/- 127. But since you also have the channel set to run that motor the cortex is sending out 2 different values. A value of 0 from the channel and a value of +/- 127 from the buttons. Causing the motor to jump between these 2 values is whats causing the jittering. Get rid of the code for the channel and it will work just fine.

#9