There are many projects to recycle old DVD players into a mini CNC Plotter based on Arduino. It is a nice project and ideal to start with its Arduino. The mechanical construction and more particularly the pencil holder can be difficult. I propose in this article to realize a mini plotter by realizing the mechanical elements by 3D printing. We will use two L293D H bridges to drive the engines of the DVD players. We find it for less than €2 in China. You can develop your mini CNC Plotter directly from this post.

Contents

1 Step 1 : BOM
2 Step 2 : Prepare translation systems
3 Step 3 : Prepare stepper motors (X and Y axis)
4 Step 4 : Print 3D parts
5 Step 5 : Prepare the plywood structure
6 Step 6 : Prepare the circuit
7 Step 7 : Assembling the Mini CNC Plotter
- 7.1 Breadboard and Arduino
8 Step 8 : Setup X and Y axis
9 Step 9 : Upload the CNC code into the Arduino
10 Step 10 : Install Processing or use gctrl.exe
11 Step 11 : Plot your first draw with gctrl

Step 1 : BOM

You can buy all components on internet or DIY store.

1x Arduino Uno
1x Breadboard 400 points
2x L293D motor drives
1x servo motor SG90
2 old CD/DVD players
2 wires 22AWG (yellow) 15cm (0.6 in)
2 wires 22AWG (green) 15cm (0.6 in)
2 wires 22AWG (red) 15cm (0.6 in)
2 wires 22AWG (white) 15cm (0.6 in)
Some shrink tubing
1x plywood sheet 200 x 160mm (7.87 in x 6.3 in) for X Axis.Thickness : 10mm (0.39in) or 5mm plexiglass (0.2 in)
2x plywood sheet 150 x 50mm (5.91 in x 0.2 in) for Y Axis.
1x plexiglass plate (0.2 in) 76 x 76 mm (size of a post it, 3 x 3 in)
1x 3mm rod (0.12 in) x 80 mm (3.15 in)
Glue gun
2x screw M2 or glue to fix servo
8x M4x35mm and nuts
1x screw M5x20mm and nut

Step 2 : Prepare translation systems

Dismantle the old DVD players to get the translation system with the stepper motor.

mini traceur cnc plotter projets diy lecteur dvd — Stepper Motor and DVD player translation system ready to use.

Step 3 : Prepare stepper motors (X and Y axis)

It’s better to sold the wires on the flexible connector. You may have problems if you sold directly on the stepper motor. If you can, try to use 4 different colors, one for each Pin. There is no identification on the engine but the connection is quite simple. The first wire corresponds to the first output of the L293D (usually) and so on.

mini traceur cnc plotter soudure stepper motor projetdisy

mini traceur cnc plotter soudure stepper motor gaine thermo projetdisy

Step 4 : Print 3D parts

You can download the STL files of this project onThingiverse or Cults3D.

Part	3D design	Number
Mounting brackets (X axis)		4x
Spacers		8x
Breadboard spacers		4x
Z axis basis		1x
Pencil case (8mm diam.)		1x
Pencil anti-tilt ring		1x

I prefer to use PLA filament because it’s an environmental friendly and non toxic material. If you print all parts, you need about 3 hours. I use the French 3D printer Dagoma discovery200.

Step 5 : Prepare the plywood structure

Just cut the 3 parts (see the BOM for dimensions)

Step 6 : Prepare the circuit

The circuit is really easy as you can see bellow. One L293D for each axis and a servo motor for the Z-axis.

mini traceur cnc plotter arduino projet diy cablage l293d breadboard — 2x L293D motor divers

mini traceur cnc plotter arduino projet diy zoom cablage arduino — Arduino Uno

Step 7 : Assembling the Mini CNC Plotter

X and Y Axis

Use 4 spacers and 4 screws M4 x 30mm to assembling the X axis on the playwood (200 x 160mm). Do the same for the Y axis. Use the picture bellow to setup the position of elements. Finally attach the Y axis on the vertical uprights. The height is not important, we just need to adjust the position of the pen in its holder.

Drawing surface

Use a glue gun to fix the drawing surface on the axis. To find the good position move the stepper motor to the max. position and fix it.

mini traceur cnc plotter arduino projet diy zoom plateau dessin — Drawing surface (front vue)

Pencil case (Z-axis)

Follow the drawing to assembly the pencil holder. Fix the servo motor with 2x M2 screws or glue.

mini traceur cnc plotter arduino vue ensemble porte crayon — Pencil holder design

mini traceur cnc plotter arduino projet diy zoom gauche porte crayon — Pencil holder (left vue)

mini traceur cnc plotter arduino projet diy zoom droit porte crayon — Pencil holder (right vue) with the servo motor

Breadboard and Arduino

Use spacers to fix the breadboard.

mini traceur cnc plotter arduino projet diy arriere breadboard — Breadboard and Arduino (rear vue)

Step 8 : Setup X and Y axis

Now, we can start programming ! First, we need to test if the X and Y axis are properly connected. After that, we will calibrate the stepper motors.

X axis test

X-Axis use the pins 8,9,10 and 11 by default. Start this program. If all is correct, the stepper motor must do 100 steps. Measure the distance and divide by 100 to obtain the X-Axis calibration value.

/*
  Mini Traceur Arduino (CNC Plotter)
  Test X Axis
  Projets DIY 02/2016
*/
#include &lt;Stepper.h&gt;			// Include the stepper Motor librarie 

const int pasParRotation = 20; 	        // Number of steps by turn. Standard value for CD/DVD
 
// Indicate X axis stepper motor Pins 
Stepper myStepperX(pasParRotation, 8,9,10,11); 
 
void setup() {
 myStepperX.setSpeed(100);		// Stepper motor speed
 // Indicate the number of steps the drive need to do. 
 // CD/DVD drive can do about 250 steps max.
 // Negative number to reverse direction of the movement
 myStepperX.step(100);		        // Measure the distance the pencil move to calculate X calibration value	
 delay(100);
}
 
void loop() {}

Mini Traceur Arduino (CNC Plotter)

Test X Axis

Projets DIY 02/2016

#include <Stepper.h> // Include the stepper Motor librarie

const int pasParRotation = 20; // Number of steps by turn. Standard value for CD/DVD

// Indicate X axis stepper motor Pins

Stepper myStepperX(pasParRotation, 8,9,10,11);

void setup() {

myStepperX.setSpeed(100); // Stepper motor speed

// Indicate the number of steps the drive need to do.

// CD/DVD drive can do about 250 steps max.

// Negative number to reverse direction of the movement

myStepperX.step(100); // Measure the distance the pencil move to calculate X calibration value

delay(100);

}

void loop() {}

Y axis test

Do the same for the Y axis.

/*
  Mini Traceur Arduino (CNC Plotter)
  Test de l'axe Y
  Projets DIY 02/2016
*/
#include &lt;Stepper.h&gt;			//Librairie pour piloter les moteurs pas à pas
 
const int pasParRotation = 20; 	//Nombre de pas pour réaliser un tour
 
//Pins sur lesquels est relié le moteur de l'axe X
Stepper myStepperX(pasParRotation, 2,3,4,5); 
 
void setup() {
 myStepperX.setSpeed(100);		//Vitesse de déplacement
 //Indiquer le nombre de pas que le moteur pas à pas doit faire
 //Généralement un moteur de lecteur CD/DVD peut faire 250 pas au maxium
 //Indiquer un chiffre négatif pour inverser le sens de déplacement
 myStepperX.step(100);			
 delay(100);
}
 
void loop() {}

Mini Traceur Arduino (CNC Plotter)

Test de l'axe Y

Projets DIY 02/2016

#include <Stepper.h> //Librairie pour piloter les moteurs pas à pas

const int pasParRotation = 20; //Nombre de pas pour réaliser un tour

//Pins sur lesquels est relié le moteur de l'axe X

Stepper myStepperX(pasParRotation, 2,3,4,5);

void setup() {

myStepperX.setSpeed(100); //Vitesse de déplacement

//Indiquer le nombre de pas que le moteur pas à pas doit faire

//Généralement un moteur de lecteur CD/DVD peut faire 250 pas au maxium

//Indiquer un chiffre négatif pour inverser le sens de déplacement

myStepperX.step(100);

delay(100);

}

void loop() {}

In case of problem

The main problems I encountered during the development of my plotter :

The engine does not move: first check the wiring of the L293D. The IN and OUT Pins may be reversed.
The direction of movement is reversed. Reverse Pins on the L293D.
The engine never stops, do not go to the end or “jump”. There is probably an obstacle in its path. Check if one screw is not too long …

Step 9 : Upload the CNC code into the Arduino

Before uploading the CNC program, maybe you need to update the configuration

penZUp : angle of the servo when the pen is Up
penZDown : angle when the pen is Down (on the paper sheet)
Pins : servo, X and Y axis
Calibration values of the X and Y-axis

Warning: do not use the servo motor to press the pencil on the paper sheet. The force exerted by the actuator may be too strong and prevent movement of the axis X. The pen is pressed on the sheet by the spring.

/* 
 Mini Traceur CNC Arduino
 Traduction de la configuration du traceur en français et ajout d'une variable "vitesseDeplacement" permettant d'ajuster la vitesse de déplacement des axes X et Y
 Projets DIY - 02/2016
 
 D'après 
 Mini CNC Plotter firmware, based in TinyCNC https://github.com/MakerBlock/TinyCNC-Sketches
 Send GCODE to this Sketch using gctrl.pde https://github.com/damellis/gctrl
 Convert SVG to GCODE with MakerBot Unicorn plugin for Inkscape available here https://github.com/martymcguire/inkscape-unicorn
 
 More information about the Mini CNC Plotter here (german, sorry): http://www.makerblog.at/2015/02/projekt-mini-cnc-plotter-aus-alten-cddvd-laufwerken/
  */

#include &lt;Servo.h&gt;
#include &lt;Stepper.h&gt;

#define LINE_BUFFER_LENGTH 512

/*
   PARAMETRES DE CONFIGURATION
*/

const int penZUp = 130;				// Angle servomoteur, crayon relevé
const int penZDown = 40;            // Angle servomoteur, crayon baissé
const int penServoPin = 6;			// Pin sur lequel est relié le servomoteur
const int stepsPerRevolution = 20; 	// Valeur par défaut
const int vitesseDeplacement = 250;	// Vitesse de déplacement des axes X et Y

Servo penServo;  					// Objet pour actionner le servomoteur

// Initialisation des moteurs pas à pas pilotés à l'aide d'un pont H L293D
Stepper myStepperY(stepsPerRevolution, 2,3,4,5);	// Axe X         
Stepper myStepperX(stepsPerRevolution, 8,9,10,11);  // Axe Y

// Calibration, nombre de pas par millimètre
float StepsPerMillimeterX = 6.0;
float StepsPerMillimeterY = 6.0;

/*
  FIN DE LA CONFIGURATION
*/

/* 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 = 0;
int LineDelay = 50;
int penDelay = 50;

// Drawing robot limits, in mm
// OK to start with. Could go up to 50 mm if calibrated well. 
float Xmin = 0;
float Xmax = 40;
float Ymin = 0;
float Ymax = 40;
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(200);

  // Decrease if necessary
  myStepperX.setSpeed(vitesseDeplacement);
  myStepperY.setSpeed(vitesseDeplacement);  

  //  Set &amp; 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(200);
  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()&gt;0 ) {
      c = Serial.read();
      if (( c == '\n') || (c == '\r') ) {             // End of line reached
        if ( lineIndex &gt; 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 &lt;= ' ' ) {                           // 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 &gt;= LINE_BUFFER_LENGTH-1 ) {
            Serial.println( "ERROR - lineBuffer overflow" );
            lineIsComment = false;
            lineSemiColon = false;
          } 
          else if ( c &gt;= 'a' &amp;&amp; c &lt;= '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 &lt; 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 &amp; 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 &lt;= 0 ) {
          newPos.x = atof( indexX + 1); 
          newPos.y = actuatorPos.y;
        } 
        else if ( indexX &lt;= 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). 
 * Bresenham algo from https://www.marginallyclever.com/blog/2013/08/how-to-build-an-2-axis-arduino-cnc-gcode-interpreter/
 * 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 &gt;= Xmax) { 
    x1 = Xmax; 
  }
  if (x1 &lt;= Xmin) { 
    x1 = Xmin; 
  }
  if (y1 &gt;= Ymax) { 
    y1 = Ymax; 
  }
  if (y1 &lt;= 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)(x1*StepsPerMillimeterX);
  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&lt;x1 ? StepInc : -StepInc;
  int sy = y0&lt;y1 ? StepInc : -StepInc;

  long i;
  long over = 0;

  if (dx &gt; dy) {
    for (i=0; i&lt;dx; ++i) {
      myStepperX.step(sx);
      over+=dy;
      if (over&gt;=dx) {
        over-=dx;
        myStepperY.step(sy);
      }
      delay(StepDelay);
    }
  }
  else {
    for (i=0; i&lt;dy; ++i) {
      myStepperY.step(sy);
      over+=dx;
      if (over&gt;=dy) {
        over-=dy;
        myStepperX.step(sx);
      }
      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(LineDelay); 
  Zpos=Zmax; 
  if (verbose) { 
    Serial.println("Pen up!"); 
  } 
}
//  Lowers pen
void penDown() { 
  penServo.write(penZDown); 
  delay(LineDelay); 
  Zpos=Zmin; 
  if (verbose) { 
    Serial.println("Pen down."); 
  } 
}

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Mini Traceur CNC Arduino

Traduction de la configuration du traceur en français et ajout d'une variable "vitesseDeplacement" permettant d'ajuster la vitesse de déplacement des axes X et Y

Projets DIY - 02/2016

D'après

Mini CNC Plotter firmware, based in TinyCNC https://github.com/MakerBlock/TinyCNC-Sketches

Send GCODE to this Sketch using gctrl.pde https://github.com/damellis/gctrl

Convert SVG to GCODE with MakerBot Unicorn plugin for Inkscape available here https://github.com/martymcguire/inkscape-unicorn

More information about the Mini CNC Plotter here (german, sorry): http://www.makerblog.at/2015/02/projekt-mini-cnc-plotter-aus-alten-cddvd-laufwerken/

#include <Servo.h>

#include <Stepper.h>

#define LINE_BUFFER_LENGTH 512

PARAMETRES DE CONFIGURATION

const int penZUp = 130; // Angle servomoteur, crayon relevé

const int penZDown = 40; // Angle servomoteur, crayon baissé

const int penServoPin = 6; // Pin sur lequel est relié le servomoteur

const int stepsPerRevolution = 20; // Valeur par défaut

const int vitesseDeplacement = 250; // Vitesse de déplacement des axes X et Y

Servo penServo; // Objet pour actionner le servomoteur

// Initialisation des moteurs pas à pas pilotés à l'aide d'un pont H L293D

Stepper myStepperY(stepsPerRevolution, 2,3,4,5); // Axe X

Stepper myStepperX(stepsPerRevolution, 8,9,10,11); // Axe Y

// Calibration, nombre de pas par millimètre

float StepsPerMillimeterX = 6.0;

float StepsPerMillimeterY = 6.0;

FIN DE LA CONFIGURATION

/* 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 = 0;

int LineDelay = 50;

int penDelay = 50;

// Drawing robot limits, in mm

// OK to start with. Could go up to 50 mm if calibrated well.

float Xmin = 0;

float Xmax = 40;

float Ymin = 0;

float Ymax = 40;

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(200);

// Decrease if necessary

myStepperX.setSpeed(vitesseDeplacement);

myStepperY.setSpeed(vitesseDeplacement);

// 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(200);

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).

* Bresenham algo from https://www.marginallyclever.com/blog/2013/08/how-to-build-an-2-axis-arduino-cnc-gcode-interpreter/

* 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)(x1*StepsPerMillimeterX);

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.step(sx);

over+=dy;

if (over>=dx) {

over-=dx;

myStepperY.step(sy);

}

delay(StepDelay);

}

else {

for (i=0; i<dy; ++i) {

myStepperY.step(sy);

over+=dx;

if (over>=dy) {

over-=dy;

myStepperX.step(sx);

}

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(LineDelay);

Zpos=Zmax;

if (verbose) {

Serial.println("Pen up!");

}

// Lowers pen

void penDown() {

penServo.write(penZDown);

delay(LineDelay);

Zpos=Zmin;

if (verbose) {

Serial.println("Pen down.");

}

Step 10 : Install Processing or use gctrl.exe

Last step before your first draw. We need to install a program that send gcode file to the Arduino controler.

If you are a Windows user you can directly use the compilated version of gctrl. You can download it here.

For macOS or Linux users, you need to install Processing (here) then run gctrl.pde (download here)

Step 11 : Plot your first draw with gctrl

Before making your first draw :

Make sure the plot surface is at the origine.
Check that nothing blocks the movement of the axes
Place a sheet on the drawing area

gctrl is an efficient but basic program in the sense that it does not check the selected file. The plotter start just after the selection of the gcode file. So, be sure before validate. In case of problem, press “x” !

Press “p” to choose the serial port.
Press “h” to go at home position
Press “g” to chose the gcode file

A short video (in french at the moment…be patient) that explains how to make your Mini CNC plotter.

I hope you find everything you need to make your Mini CNC Plotter. I hope I did not forget anything. Feel free to share your experience or add your tricks. Comments are there for.

Itihash

What i need to do for test X & Y axis?
- Projets DIY
  
  Hi Itihash. Can you tell at what step your are ?
  - Itihash
    
    I’ll make it so i following you but i didn’t understand the step 8.
    - Projets DIY
      
      OK. We want to know how many steps are needed to move the pencil (for example 10mm). So, run X drive with 100 steps, after measure the distance (x) and then divide 100/x mm. Now replace the value of the variable StepsPerMillimeterX (by default, it 6s/mm) . Do the same for the Y axis. After that, the X and Y axis are ready. I hope it’s clear enough now. Have a good day. Christophe
      - Itihash
        
        I can do it using gctrl or I need another application?
      - Projets DIY
        
        No. Use the Arduino IDE. Create a new file (for example TestX.ino) and past the code of the step 8 (X axis step). Start the program and do as indicate before. Do the same for the Y axis (or just change the Pins of the Y stepper motor). I’m sorry i forgot to translate in English the comments… but now, i’m sure you read French very well ;-). Bye
      - Itihash
        
        Thanks.
greg

Isn’t a little mistake on connection from axis Y , l293d and pin 11 (white path) on breadboard? I guess it should be on oposite pins for l293d ?
- Projets DIY
  
  Hi Greg. You probably right. Depending your drive, you may need to switch pins to find the correct direction. I hope you’ll succeed with your project. See you soon.
Itihash

Step 6
I haven’t find similarity between drawing and real photo.
Mahadi

I have this error please help…….

Arduino: 1.8.1 (Windows 7), Board: “Arduino/Genuino Uno”

cnc_plotter:14: error: #include expects “FILENAME” or

#include <Servo.h>

^

cnc_plotter:15: error: #include expects “FILENAME” or

#include <Stepper.h>

^

exit status 1
#include expects “FILENAME” or

This report would have more information with
“Show verbose output during compilation”
option enabled in File -> Preferences.
- Projets DIY
  
  Hi Mahadi. You need to install the servo library. You just need to install it directly from the library manager (sketch menu). After that, you can download the program. Have a good day.
  - Mahadi
    
    I add it but the error remain same …why…?
    
    cnc_plotter:18: error: #include expects “FILENAME” or
    
    #include <Servo.h>
    
    ^
    
    cnc_plotter:19: error: #include expects “FILENAME” or
    
    #include <Stepper.h>
    
    ^
    
    exit status 1
    #include expects “FILENAME” or
    - Projets DIY
      
      Sorry Mahadi, it’s totally impossible to help you like that. Could you send me your sketch by using the contact form. Thank’s
      - Mahadi
        
        I Figure-out the problem and fix it …But now i got a serious problem about G- Code making …Can u Please tell me How can i generate G-Code With out inkscape ?
        
        Actually i Use inkscape 0.48.5 version and also it’s plugin But i don’t find g code export …option.. So..How can i Generate G- Code .?
        And How you generate G code For Yourself.
      - Projets DIY
        
        Hello Mahadi. I’m glad if you found the solution ! To prepare your gcode files, just follow this post https://www.diyprojects.io/prepare-gcode-gctrl-files-inkscape-unicorn-makerbot-extension/
        See you soon
Mahadi

Can u Please tell me How can i generate G-Code With out inkscape ?

Actually i Use inkscape 0.48.5 version and also it’s plugin But i don’t find g code option.. So..How can i Generate G- Code now..?
bujari

I did all steps like you but the stepper motors are not running. The servo motor is running but the steps not. can you help me please
- Projets DIY
  
  Hi Bujari. Can you tell me how you power the stepper motors? May be that there is not enough power. The problem with recycling stepper motors from older dvd drives is that you do not know pin marking. You have to look for the right wiring. See you soon.
  - bujari
    
    I tried by stepper test, is running properly.
    Power I tried 12V and 9V the same.
kro-nos

Hi, please help me.
Have same error as Mahadi….

Arduino: 1.8.3 (Windows 7), Board: “Arduino/Genuino Uno”
cnc_plotter:14: error: #include expects “FILENAME” or etc…

Included servo and stepper libraries as suggested from sketch menu
but still the same error.
I am not an expert please may you give me detailed info on how to solve.
Thanks a lot.
Sadanand Kale

I have problem when I’m trying to execute g code… It’s just showed…. Loading file…. And nothing….. What to do
- kro-nos
  
  Solved.
  Thanks
  - Projets DIY
    
    Great. Maybe you could explain to everyone how you solved the problem. Thank’s
Sadam Lubowa

hi am called sadam i have got a problem i have used the same wiring and code used but my cd rom stepper motor they dont move at all think the problem it ld293 ic but i have just bought them what can i do now because am stack
Eduardo A. Díaz Mesa

Hi, very, very good project, I see that many people have been successful.

I have uploaded Test_X_Axis_CNC_Plotter and Y, and my engines have good movement.

I have a problem with gctrl.pde and gctrl.exe, but I do not know why. My engines have no movement with gctrl. Select the serial port (OK), use the arrows and no movement, load a gcode image with (G) and no movement. I do not know where the problem is.

You help me? Thank you

My beta-CNC without Arduino, only router with OpenWRT and L293 driver. Does not interpret GCODE yet:
- Projets DIY
  
  Hello Eduardo. Great project. I’m sorry but I have no skills on openwrt (at the moment ;-))

Make a Mini CNC Plotter with old DVD players Arduino and L293D

Step 1 : BOM

Step 2 : Prepare translation systems

Step 3 : Prepare stepper motors (X and Y axis)

Step 4 : Print 3D parts

Step 5 : Prepare the plywood structure

Step 6 : Prepare the circuit

Step 7 : Assembling the Mini CNC Plotter

X and Y Axis

Drawing surface

Pencil case (Z-axis)

Breadboard and Arduino

Step 8 : Setup X and Y axis

X axis test

Y axis test

In case of problem

Step 9 : Upload the CNC code into the Arduino

Step 10 : Install Processing or use gctrl.exe

Step 11 : Plot your first draw with gctrl

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