[SOLVED]The program enters the switch case but doesn't run the function ... !?

Using Arduino Programming Questions
1

Greetings,

I have a weird problem about a bit of code.

//define pin numbers
const int directionPin = 2;// direction
const int stepPin = 5;// step

...

int detectorLeft = 9; // Left stop sensor
int detectorRight = 11; // right stop sensor
...

// define variables
const int ritardo = 50; // Minimum = 50
int inputCode = 2; // Default is 2 => the machine is stopped
boolean valD;
boolean valL;
...

// declare functions
...
void stepRight(int steps);
void stepLeft(int steps);

void setup()
{
  Serial.begin (9600);

  pinMode(detectorRight, INPUT);
  pinMode(detectorLeft, INPUT);

  pinMode(stepPin, OUTPUT);
  pinMode(directionPin, OUTPUT);
 ...

  delay(300);
}

void loop() {
  if (Serial.available() > 0) {
    // read the incoming integer
    inputCode = Serial.parseInt();
  }

  switch (inputCode) {
 ...
    case 9  :
      Serial.println("Enter 9");
      stepLeft(1000);
      break; /* optional */

    case 10  :
      Serial.println("Enter 10");
      stepRight(1000);
      break; /* optional */

    default :
      break;
  }
}

...

/* One or multiple steps to the right */
void stepLeft(int steps) {
  int count = 0;
  while (count < steps) {
    valL = digitalRead(detectorRight);
    digitalWrite(directionPin, LOW);
    count++;
    if (valL == 1) {
      digitalWrite(stepPin, HIGH);
      delayMicroseconds(ritardo);
      digitalWrite(stepPin, LOW);
      delayMicroseconds(ritardo);
    } else {
      digitalWrite(stepPin, LOW);
    }
  }
  inputCode = 2;
}

/* One or multiple steps to the left */
void stepRight(int steps) {
  int count = 0;
  while (count < steps) {
    valD = digitalRead(detectorLeft);
    digitalWrite(directionPin, HIGH);
    count++;
    if (valL == 1) {
      digitalWrite(stepPin, HIGH);
      delayMicroseconds(ritardo);
      digitalWrite(stepPin, LOW);
      delayMicroseconds(ritardo);
    } else {
      digitalWrite(stepPin, LOW);
    }
  }
  inputCode = 2;
}

Here is what's happening. When I upload the code and then open the serial monitor, I send the input 10. The monitor prints the message but nothing happens (my stepper motor doesn't run). Then when I type 9 (or anything else), the respective function is called and only now if I type 10, the stepRight() function is called too. it is really weird. I've done a ton of tests and the observations are :

  • case switch above 9 don't work (I've tried with case 11) when they're first called after an upload.
  • One case switch between 1-9 has to be called before
  • The print message is always called (so the program enters the switch case) but the stepRight() is not called.

Thanks for your help

2

What have you got the Line ending set to in the Serial monitor ?

3

UKHeliBob:
What have you got the Line ending set to in the Serial monitor ?

"No line ending" and also, the baud in the monitor is set to 9600 (so no problem there either).

4

Can stop sensors prevent movement?

Do you have pull up/pull down resistors?
Otherwise an input pin will be open and read HIGH and LOW randomly, unless its closed.

If not use built-in pull up resistors. (remember that open switch is HIGH and closed is LOW)

  pinMode(detectorRight, INPUT_PULLUP);
  pinMode(detectorLeft, INPUT_PULLUP);
5

I found the problem. It was a silly one. In the stepRight() function, I was storing the detector value in valD but I was checking valL (unlike the stepLeft() function in which I was storing in valL and checking valL).

Sorry to bother you with this silly problem. I dont see a "solve" button, tell me if there is one to close this thread.

Yours

6

You can edit the title in the first post via the 'More' button. Usually folks add [SOLVED]