Arduino with stepper motor

Projects Programming
1

hi i am trying to control the stepper motor through GUI built on python.. i have written a code such that when i recieved a character from the GUI motor should rotate

in the Arduino serial monitor after reading a character it will end up with -1

here is my code please help

int motorPin1 = 8; // stepper motor pins connected to pin 8,9,10,11 of the arduino
int motorPin2 = 9;
int motorPin3 = 10;
int motorPin4 = 11;

int delayTime = 100; // delay time of half second
int incomingByte = 0; // for incoming serial data
int x,y;

void steppermotor(int dir, int ang);

void setup()
{
pinMode(motorPin1, OUTPUT);
pinMode(motorPin2, OUTPUT);
pinMode(motorPin3, OUTPUT);
pinMode(motorPin4, OUTPUT);

Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
}

void loop()
{

if (Serial.available() > 0)
{
Serial.println(incomingByte = Serial.read());

/the variable x is taken for to select clockwise or anticlockwise/

if (incomingByte == 97) // decimal value for a is 97
{
x = 0;
}

else if (incomingByte == 98) // decimal value for b is 98
{
x = 1;
}

Serial.println(incomingByte = Serial.read());

if (incomingByte == 99) // decimal value for c is 99
{
y = 90; //the variable y is taken for to select clockwise or anticlockwise
}

else if (incomingByte == 100) // decimal value for d is 100
{
y = 180;
}

else if (incomingByte == 101) // decimal value for e is 101
{
y = 270;
}

else if (incomingByte == 102) // decimal value for f is 102
{
y = 360;
}

steppermotor(x,y); // the variable dir is passed to x and variable y is passed to ang (dir = direction,ang = angle)

}

}

void steppermotor(int dir, int ang)
{
if(dir == 1)
{
for(int p=0; p<ang/7.2; p++) // condition p = ang/1.8*4
{
digitalWrite(motorPin1, HIGH);
digitalWrite(motorPin2, LOW);
digitalWrite(motorPin3, LOW);
digitalWrite(motorPin4, LOW);
delay(delayTime);

digitalWrite(motorPin1, LOW);
digitalWrite(motorPin2, HIGH);
digitalWrite(motorPin3, LOW);
digitalWrite(motorPin4, LOW);
delay(delayTime);

digitalWrite(motorPin1, LOW);
digitalWrite(motorPin2, LOW);
digitalWrite(motorPin3, HIGH);
digitalWrite(motorPin4, LOW);
delay(delayTime);

digitalWrite(motorPin1, LOW);
digitalWrite(motorPin2, LOW);
digitalWrite(motorPin3, LOW);
digitalWrite(motorPin4, HIGH);
delay(delayTime);
}
}

if (dir ==0)
{
for(int p=0; p<ang/7.2; p++)
{
digitalWrite(motorPin1, LOW);
digitalWrite(motorPin2, HIGH);
digitalWrite(motorPin3, HIGH);
digitalWrite(motorPin4, HIGH);
delay(delayTime);

digitalWrite(motorPin1, HIGH);
digitalWrite(motorPin2, HIGH);
digitalWrite(motorPin3, HIGH);
digitalWrite(motorPin4, LOW);
delay(delayTime);

digitalWrite(motorPin1, HIGH);
digitalWrite(motorPin2, HIGH);
digitalWrite(motorPin3, LOW);
digitalWrite(motorPin4, HIGH);
delay(delayTime);

digitalWrite(motorPin1, HIGH);
digitalWrite(motorPin2, LOW);
digitalWrite(motorPin3, HIGH);
digitalWrite(motorPin4, HIGH);
delay(delayTime);

}
}

}

Screenshot-2.png
Screenshot-2.png1280×800 52.7 KB

2

Only one application on the PC can be on the end of the serial port. If the Python app is that application, the Serial Monitor can not be used. If the Serial Monitor is that app, the Python app can't talk to the Arduino.

if (incomingByte == 97)   // decimal value for a is 97

should be

if (incomingByte == 'a')   // No comment needed
3

You have the classic problem with Serial.available:

Serial.println(incomingByte = Serial.read());

            if (incomingByte == 99)   // decimal value for c is 99     
             {
                  y = 90; //the variable y is taken for to select clockwise or anticlockwise
             }

This Serial.read has no guarantee that there is anything to read and if there is not, it returns -1, as you observe. You need to check with Serial.available as you did for the first read and likely wait until there is something.