Programming Help

VEX V5 General Discussion
#1

Hi,
I’m wondering if there is a way for one button to make an arm go at a certain potentiometer value.
For example i press Btn5U and the arm would go at a potentiometer value of 1500. Then 5D is pressed to go all the way down. Then 5U again but to go at the potentiometer value of 1300.

thanks

#2

You need a PID loop for this, you can set the target value to the potentiometer height and the control loop will bring the lift there.

Please see https://vexforum.com/t/a-pid-controller-in-robotc/20105/1

and try not to bump it :stuck_out_tongue:

#3

Well, if you don’t need the arm height to be precise and the arm is not overly powered, you could probably do it with a simple while loop. You can also set a “flag” that keeps track of whether or not you have already gone up to a pot value of 1500 in a previous command. Then you can toggle that flag value depending on what you did in a previous command.

The concept is roughly something like this:

if Btn5U is pressed and Flag = 0
while (ArmPotValue < 1500)
arm motors raise up
so when ArmPotValue > 1500, you stop the motors and toggle the Flag =1

if Btn5U is pressed and Flag = 1
while (ArmPotValue < 1300)
arm motors raise up
so when ArmPotValue > 1300, you stop the motors and toggle the Flag =0

Note that if the arm overshoots the desired value too much, then you will need a PID control, as Dr. Gupta suggests.

#4

true, for most autons u can get away with some slop, so some shortcuts can be used like bang/bang and other stuff. Altho im not entirely sure if ur code produces the intended behavior that the OP seeks.

lmfao. I’m a sophmore in highschool. 40% triggered- 60% amused by this.

#5

Sophomore today, Dr. Gupta tomorrow. Maybe I just wanted the privilege of being the first to call you that. :slight_smile:

#6