My cnc is not working properly

I have made a cnc by using 28 byj 48 stepper motor,Arduino uno ,l293d motor shield.
I am using processing software to run the gcode . When I am drawing 10cm square it draws a 1cm square or any figure which i want to draw it tiny one
Please help me .If I have made any mistakes in the programming of the arduino please help me out to figure it out.
My code

#include <Servo.h>
#include <AFMotor.h>

#define LINE_BUFFER_LENGTH 512

char STEP = MICROSTEP ;

// Servo position for Up and Down
const int penZUp = 120;
const int penZDown = 50;

// Servo on PWM pin 10
const int penServoPin =10 ;

// Should be right for DVD steppers, but is not too important here
const int stepsPerRevolution = 4096;

// create servo object to control a servo
Servo penServo;

// Initialize steppers for X- and Y-axis using this Arduino pins for the L293D H-bridge
AF_Stepper myStepperY(stepsPerRevolution,1);
AF_Stepper myStepperX(stepsPerRevolution,2);

/* Structures, global variables */
struct point {
float x;
float y;
float z;
};

// Current position of plothead
struct point actuatorPos;

// Drawing settings, should be OK
float StepInc = 1;
int StepDelay = 1;
int LineDelay =0;
int penDelay = 50;

// Motor steps to go 1 millimeter.
// Use test sketch to go 100 steps. Measure the length of line.
// Calculate steps per mm. Enter here.
float StepsPerMillimeterX = 200.0;
float StepsPerMillimeterY = 200.0;

// Drawing robot limits, in mm
// OK to start with. Could go up to 50 mm if calibrated well.
float Xmin = 0;
float Xmax = 200;
float Ymin = 0;
float Ymax = 200;
float Zmin = 0;
float Zmax = 1;

float Xpos = Xmin;
float Ypos = Ymin;
float Zpos = Zmax;

// Set to true to get debug output.
boolean verbose = false;

// Needs to interpret
// G1 for moving
// G4 P300 (wait 150ms)
// M300 S30 (pen down)
// M300 S50 (pen up)
// Discard anything with a (
// Discard any other command!

/**********************

  • void setup() - Initialisations
    ***********************/
    void setup() {
    // Setup

Serial.begin( 9600 );

penServo.attach(penServoPin);
penServo.write(penZUp);
delay(100);

// Decrease if necessary
myStepperX.setSpeed(220);

myStepperY.setSpeed(220);

// Set & move to initial default position
// TBD

// Notifications!!!
Serial.println("Mini CNC Plotter alive and kicking!");
Serial.print("X range is from ");
Serial.print(Xmin);
Serial.print(" to ");
Serial.print(Xmax);
Serial.println(" mm.");
Serial.print("Y range is from ");
Serial.print(Ymin);
Serial.print(" to ");
Serial.print(Ymax);
Serial.println(" mm.");
}

/**********************

  • void loop() - Main loop
    ***********************/
    void loop()
    {

delay(100);
char line[ LINE_BUFFER_LENGTH ];
char c;
int lineIndex;
bool lineIsComment, lineSemiColon;

lineIndex = 0;
lineSemiColon = false;
lineIsComment = false;

while (1) {

// Serial reception - Mostly from Grbl, added semicolon support
while ( Serial.available()>0 ) {
  c = Serial.read();
  if (( c == '\n') || (c == '\r') ) {             // End of line reached
    if ( lineIndex > 0 ) {                        // Line is complete. Then execute!
      line[ lineIndex ] = '\0';                   // Terminate string
      if (verbose) { 
        Serial.print( "Received : "); 
        Serial.println( line ); 
      }
      processIncomingLine( line, lineIndex );
      lineIndex = 0;
    } 
    else { 
      // Empty or comment line. Skip block.
    }
    lineIsComment = false;
    lineSemiColon = false;
    Serial.println("ok");    
  } 
  else {
    if ( (lineIsComment) || (lineSemiColon) ) {   // Throw away all comment characters
      if ( c == ')' )  lineIsComment = false;     // End of comment. Resume line.
    } 
    else {
      if ( c <= ' ' ) {                           // Throw away whitepace and control characters
      } 
      else if ( c == '/' ) {                    // Block delete not supported. Ignore character.
      } 
      else if ( c == '(' ) {                    // Enable comments flag and ignore all characters until ')' or EOL.
        lineIsComment = true;
      } 
      else if ( c == ';' ) {
        lineSemiColon = true;
      } 
      else if ( lineIndex >= LINE_BUFFER_LENGTH-1 ) {
        Serial.println( "ERROR - lineBuffer overflow" );
        lineIsComment = false;
        lineSemiColon = false;
      } 
      else if ( c >= 'a' && c <= 'z' ) {        // Upcase lowercase
        line[ lineIndex++ ] = c-'a'+'A';
      } 
      else {
        line[ lineIndex++ ] = c;
      }
    }
  }
}

}
}

void processIncomingLine( char* line, int charNB ) {
int currentIndex = 0;
char buffer[ 64 ]; // Hope that 64 is enough for 1 parameter
struct point newPos;

newPos.x = 0.0;
newPos.y = 0.0;

// Needs to interpret
// G1 for moving
// G4 P300 (wait 150ms)
// G1 X60 Y30
// G1 X30 Y50
// M300 S30 (pen down)
// M300 S50 (pen up)
// Discard anything with a (
// Discard any other command!

while( currentIndex < charNB ) {
switch ( line[ currentIndex++ ] ) { // Select command, if any
case 'U':
penUp();
break;
case 'D':
penDown();
break;
case 'G':
buffer[0] = line[ currentIndex++ ]; // /!\ Dirty - Only works with 2 digit commands
// buffer[1] = line[ currentIndex++ ];
// buffer[2] = '\0';
buffer[1] = '\0';

  switch ( atoi( buffer ) ){                   // Select G command
  case 0:                                   // G00 & G01 - Movement or fast movement. Same here
  case 1:
    // /!\ Dirty - Suppose that X is before Y
    char* indexX = strchr( line+currentIndex, 'X' );  // Get X/Y position in the string (if any)
    char* indexY = strchr( line+currentIndex, 'Y' );
    if ( indexY <= 0 ) {
      newPos.x = atof( indexX + 1); 
      newPos.y = actuatorPos.y;
    } 
    else if ( indexX <= 0 ) {
      newPos.y = atof( indexY + 1);
      newPos.x = actuatorPos.x;
    } 
    else {
      newPos.y = atof( indexY + 1);
      indexY = '\0';
      newPos.x = atof( indexX + 1);
    }
    drawLine(newPos.x, newPos.y );
    //        Serial.println("ok");
    actuatorPos.x = newPos.x;
    actuatorPos.y = newPos.y;
    break;
  }
  break;
case 'M':
  buffer[0] = line[ currentIndex++ ];        // /!\ Dirty - Only works with 3 digit commands
  buffer[1] = line[ currentIndex++ ];
  buffer[2] = line[ currentIndex++ ];
  buffer[3] = '\0';
  switch ( atoi( buffer ) ){
  case 300:
    {
      char* indexS = strchr( line+currentIndex, 'S' );
      float Spos = atof( indexS + 1);
      //         Serial.println("ok");
      if (Spos == 30) { 
        penDown(); 
      }
      if (Spos == 50) { 
        penUp(); 
      }
      break;
    }
  case 114:                                // M114 - Repport position
    Serial.print( "Absolute position : X = " );
    Serial.print( actuatorPos.x );
    Serial.print( "  -  Y = " );
    Serial.println( actuatorPos.y );
    break;
  default:
    Serial.print( "Command not recognized : M");
    Serial.println( buffer );
  }
}

}

}

/*********************************

  • Draw a line from (x0;y0) to (x1;y1).
  • int (x1;y1) : Starting coordinates
  • int (x2;y2) : Ending coordinates
    **********************************/
    void drawLine(float x1, float y1) {

if (verbose)
{
Serial.print("fx1, fy1: ");
Serial.print(x1);
Serial.print(",");
Serial.print(y1);
Serial.println("");
}

// Bring instructions within limits
if (x1 >= Xmax) {
x1 = Xmax;
}
if (x1 <= Xmin) {
x1 = Xmin;
}
if (y1 >= Ymax) {
y1 = Ymax;
}
if (y1 <= Ymin) {
y1 = Ymin;
}

if (verbose)
{
Serial.print("Xpos, Ypos: ");
Serial.print(Xpos);
Serial.print(",");
Serial.print(Ypos);
Serial.println("");
}

if (verbose)
{
Serial.print("x1, y1: ");
Serial.print(x1);
Serial.print(",");
Serial.print(y1);
Serial.println("");
}

// Convert coordinates to steps
x1 = (int)(x1StepsPerMillimeterX);
y1 = (int)(y1
StepsPerMillimeterY);
float x0 = Xpos;
float y0 = Ypos;

// Let's find out the change for the coordinates
long dx = abs(x1-x0);
long dy = abs(y1-y0);
int sx = x0<x1 ? StepInc : -StepInc;
int sy = y0<y1 ? StepInc : -StepInc;

long i;
long over = 0;

if (dx > dy) {
for (i=0; i<dx; ++i) {
myStepperX.onestep(sx,STEP);
over+=dy;
if (over>=dx) {
over-=dx;
myStepperY.onestep(sy,STEP);
}
delay(StepDelay);
}
}
else {
for (i=0; i<dy; ++i) {
myStepperY.onestep(sy,STEP);
over+=dx;
if (over>=dy) {
over-=dy;
myStepperX.onestep(sx,STEP);
}
delay(StepDelay);
}
}

if (verbose)
{
Serial.print("dx, dy:");
Serial.print(dx);
Serial.print(",");
Serial.print(dy);
Serial.println("");
}

if (verbose)
{
Serial.print("Going to (");
Serial.print(x0);
Serial.print(",");
Serial.print(y0);
Serial.println(")");
}

// Delay before any next lines are submitted
delay(LineDelay);
// Update the positions
Xpos = x1;
Ypos = y1;
}

// Raises pen
void penUp() {
penServo.write(penZUp);
delay(penDelay);
Zpos=Zmax;
digitalWrite(15, LOW);
digitalWrite(16, HIGH);
if (verbose) {
Serial.println("Pen up!");

}
}
// Lowers pen
void penDown() {
penServo.write(penZDown);
delay(penDelay);
Zpos=Zmin;
digitalWrite(15, HIGH);
digitalWrite(16, LOW);
if (verbose) {
Serial.println("Pen down.");

}
}

Read that back to yourself.
Now, put yourself in our shoes.

Get back to us.

And take the time to print the G-code output on PAPER and study each line to see if you can spot the problem.
Paul

Your stepper motor draws in steps. The GCODE is in arbitrary units. The code that converts GCODE to steps need to use the correct conversion. Sounds like you have that conversion wrong.

I have given the code can you say where Imade a mistake.
And how to correct the conversion

What you actually want to say

Maybe that's where the problem is.

Please remember to use code tags when posting code

float StepsPerMillimeterX = 200.0;
float StepsPerMillimeterY = 200.0;

If you move 1 cm when the GCODE says to move 10 cm then you should change those two lines to:

float StepsPerMillimeterX = 2000.0;
float StepsPerMillimeterY = 2000.0;

That will cause 10 times as many steps so it will move 10 times as far: 10 cm.

I will try as you said

It didn’t solve the problem I have tried it

But you've tried other things as well - tell us about those.

Please remember to use code tags when posting code

So you changed you sketch from 200.0 steps per mm to 2000.0 steps per mm and your 10 cm square is still coming out as 1 cm? Something is VERY wrong with something.

Step 1: Show your GCODE!

Step 2: Change 'verbose' to true and re-upload your sketch. If it doesn't already, change the Processing sketch so it prints any characters it gets from the Arduino. Now show the output from the Processing sketch (which includes the output of the Arduino sketch).

Hi, @fayjan
Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".

Thanks.. Tom... :grinning: :+1: :coffee: :australia: