issue with stepper code works until I want to put if statement in

Other Hardware Motors, Mechanics, Power and CNC
1

The following code works until insert:
** lim1_st = digitalRead(lim1);**
** if(lim1_st == LOW);{**
** x = stepsPerRevolution;**
** }**

My intention is have a limit switch stop the stepper motor.
When I comment out just : x = stepsPerRevolution;
It works.

So that tells me for some reason x is getting set to stepsPerRevolution and making it stop.
But the pin stays high the entire time so I don't know why it enters that if statement and makes x = stepsPerRevolution;.

Thank you for your time.

// Define pin connections & motor's steps per revolution
const int dirPin = 10;
const int stepPin = 9;
const int lim1 = 2;
const int lim2 = 3;
const int remote = 1;
const int drvEN = 0;
const int stepsPerRevolution = 400;

int lim1_st = 0; //Button state initial value
int lim2_st = 0; //Button state initial value
int flag1 = 1;  //flag to keep track of button presses
int flag2 = 0;
int remote_st = 0;

void setup()
{
  // Declare pins as Outputs
  pinMode(stepPin, OUTPUT);
  pinMode(dirPin, OUTPUT);
  pinMode(lim1, INPUT);
  pinMode(lim2, INPUT);
  pinMode(remote, INPUT);
  pinMode(drvEN, OUTPUT);

  digitalWrite(drvEN, HIGH);
  
}
void loop()
{
  remote_st = digitalRead(remote);
  if(remote_st == LOW) {

    if(flag1 == 1){
      digitalWrite(drvEN,LOW);
  // Set motor direction clockwise
  digitalWrite(dirPin, HIGH);

  // Spin motor slowly
  for(int x = 0; x < stepsPerRevolution; x++)
  {
  lim2_st = digitalRead(lim2);
    if(lim2_st == LOW);{
      x = stepsPerRevolution;
    }
    digitalWrite(stepPin, HIGH);
    delayMicroseconds(2000);
    digitalWrite(stepPin, LOW);
    delayMicroseconds(2000);
  }
   digitalWrite(drvEN,HIGH);
  delay(1000); // Wait a second
  flag1 = 2;
    }
  }
  remote_st = digitalRead(remote);
if(remote_st == LOW) {
  if(flag1 == 2) {
     digitalWrite(drvEN,LOW);
  // Set motor direction counterclockwise
  digitalWrite(dirPin, LOW);

  // Spin motor quickly
  for(int x = 0; x < stepsPerRevolution; x++)
  {
  lim1_st = digitalRead(lim1);
    if(lim1_st == LOW);{
      x = stepsPerRevolution;
    }
    digitalWrite(stepPin, HIGH);
    delayMicroseconds(2000);
    digitalWrite(stepPin, LOW);
    delayMicroseconds(2000);
  }
   digitalWrite(drvEN,HIGH);
  delay(1000); // Wait a second
  flag1 = 1;
}
}
}
2

If you want to terminate a FOR loop the appropriate instruction is break;

If you don't have pull-up resistors on your limit switch pins they may be giving spurious results. It's better to use
pinMode(pin, INPUT_PULLUP); which sets the internal pull up resistor.

...R

3

Thank you for the suggestion.

I have pull up resistors on the limit switches.

I can try the internal pull-up. But still confusing why externals wouldn’t work and why the code is entering the if statement when it’s not true.

I’ll look into break. Never used before.
Thanks again!

4

The following code works until insert:

  lim1_st = digitalRead(lim1);

if(lim1_st == LOW);{
     x = stepsPerRevolution;
   }

There's an error here - the semicolon on the second line.

A lone semicolon is the empty statement which does exactly nothing. So the
whole if statement does nothing at all and x is always set to stepsPerRevolution.

5

MarkT:
There's an error here - the semicolon on the second line.

Well spotted.

...R

6

MarkT:
There's an error here - the semicolon on the second line.

A lone semicolon is the empty statement which does exactly nothing. So the
whole if statement does nothing at all and x is always set to stepsPerRevolution.

Well spotted indeed! Thank you