The stepper in the drive mechanism helps for step wise movement in X and Y direction. The X axis is controlled by the vertical placed mechanism and its stepper motor, while the Y axis is controlled by the horizontal stepper mechanism.
I have used the DVD players plastic frame itself as the base and used two wooden pieces as a support for Vertical mechanism. You are free to use your imagination and creativity to build your frames and mechanism to achieve the same.
I have connected a pen on a lever mechanism which the servo will control for Z axis motion. Using a Pen spring the pen forced to be in down position. while plotting the servo will release the pen in down and pull to UP position otherwise.
These are few images which I took while building the plotter. Again, use your own creativity to build based on available materials.
Here I have basically used wooden pieces and copper clad to setup the Y axis and vertical support. You can see black colored mechanism in these images which was later replaced with the metal one.
This is because the black one was of a CD music player. the pitch size of the gear of CD player mechanism was different with respect to DVD or CD drive which caused some trouble while initial testing. To get a proper sync in X and Y axis one must use stepper with least matching pitch in the gear.
The electronics used is a popular H-Bridge driver L293 along with Arduino Nano which will talk to PC. Arduino will also drive the stepper and servo according to target image's Gcode coordinate conveyed by Processing software.
Circuit details are given below.
Initially I tested the setup on a bread board and then I shifted to PCB. I soldered everything on a home made PCB. Ignore the quality.. it was real fun to draw everything using marker pen.
Gcode files are required or need to be generated before using the plotter. Here i will be using Inkscape software with pre installed plugin for Gcode translation.
First you have to burn the CNC code on Arduino Nano. For that connect the Nano to PC using USB port. Open the Arduino IDE and burn the code to Nano by selecting proper com port number.
Now open the Processing Software. Open the CNC plotter GCTRL code and click Play or Run. The New popup will appear. If it detected the Arduino after selecting correct com port, it will show the comment as Mini CNC plotter alive and kicking.
Now press g key on keyboard and select the path of the Gcode that we just created. Voila.. There you go.. your plotter will start plotting the image.
Arduino Code :
This is because the black one was of a CD music player. the pitch size of the gear of CD player mechanism was different with respect to DVD or CD drive which caused some trouble while initial testing. To get a proper sync in X and Y axis one must use stepper with least matching pitch in the gear.
Circuit details are given below.
Initially I tested the setup on a bread board and then I shifted to PCB. I soldered everything on a home made PCB. Ignore the quality.. it was real fun to draw everything using marker pen.
Gcode files are required or need to be generated before using the plotter. Here i will be using Inkscape software with pre installed plugin for Gcode translation.
Now open the Processing Software. Open the CNC plotter GCTRL code and click Play or Run. The New popup will appear. If it detected the Arduino after selecting correct com port, it will show the comment as Mini CNC plotter alive and kicking.
Now press g key on keyboard and select the path of the Gcode that we just created. Voila.. There you go.. your plotter will start plotting the image.
Arduino Code :
/*
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
// Servo position for Up and Down
const int penZUp = 80;
const int penZDown = 40;
// Servo on PWM pin 6
const int penServoPin = 6;
// Should be right for DVD steppers, but is not too important here
const int stepsPerRevolution = 20;
// 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
Stepper myStepperY(stepsPerRevolution, 2,3,4,5);
Stepper myStepperX(stepsPerRevolution, 8,9,10,11);
/* 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;
// 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 = 6.0;
float StepsPerMillimeterY = 6.0;
// 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(250);
myStepperY.setSpeed(250);
// 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.");
}
}
Processing GCTRL Code :
import java.awt.event.KeyEvent;
import javax.swing.JOptionPane;
import processing.serial.*;
Serial port = null;
// select and modify the appropriate line for your operating system
// leave as null to use interactive port (press 'p' in the program)
String portname = null;
//String portname = Serial.list()[0]; // Mac OS X
//String portname = "/dev/ttyUSB0"; // Linux
//String portname = "COM6"; // Windows
boolean streaming = false;
float speed = 0.001;
String[] gcode;
int i = 0;
void openSerialPort()
{
if (portname == null) return;
if (port != null) port.stop();
port = new Serial(this, portname, 9600);
port.bufferUntil('\n');
}
void selectSerialPort()
{
String result = (String) JOptionPane.showInputDialog(frame,
"Select the serial port that corresponds to your Arduino board.",
"Select serial port",
JOptionPane.QUESTION_MESSAGE,
null,
Serial.list(),
0);
if (result != null) {
portname = result;
openSerialPort();
}
}
void setup()
{
size(600, 400);
openSerialPort();
}
void draw()
{
background(155);
fill(0);
int y = 24, dy = 12;
text("INSTRUCTIONS", 12, y); y += dy;
text("p: select serial port", 12, y); y += dy;
text("1: set speed to 0.001 inches (1 mil) per jog", 12, y); y += dy;
text("2: set speed to 0.010 inches (10 mil) per jog", 12, y); y += dy;
text("3: set speed to 0.100 inches (100 mil) per jog", 12, y); y += dy;
text("arrow keys: jog in x-y plane", 12, y); y += dy;
text("page up & page down: jog in z axis", 12, y); y += dy;
text("$: display grbl settings", 12, y); y+= dy;
text("h: go home", 12, y); y += dy;
text("0: zero machine (set home to the current location)", 12, y); y += dy;
text("g: stream a g-code file", 12, y); y += dy;
text("x: stop streaming g-code (this is NOT immediate)", 12, y); y += dy;
y = height - dy;
text("current jog speed: " + speed + " inches per step", 12, y); y -= dy;
text("current serial port: " + portname, 12, y); y -= dy;
}
void keyPressed()
{
if (key == '1') speed = 0.001;
if (key == '2') speed = 0.01;
if (key == '3') speed = 0.1;
if (!streaming) {
if (keyCode == LEFT) port.write("G91\nG20\nG00 X-" + speed + " Y0.000 Z0.000\n");
if (keyCode == RIGHT) port.write("G91\nG20\nG00 X" + speed + " Y0.000 Z0.000\n");
if (keyCode == UP) port.write("G91\nG20\nG00 X0.000 Y" + speed + " Z0.000\n");
if (keyCode == DOWN) port.write("G91\nG20\nG00 X0.000 Y-" + speed + " Z0.000\n");
if (keyCode == KeyEvent.VK_PAGE_UP) port.write("G91\nG20\nG00 X0.000 Y0.000 Z" + speed + "\n");
if (keyCode == KeyEvent.VK_PAGE_DOWN) port.write("G91\nG20\nG00 X0.000 Y0.000 Z-" + speed + "\n");
if (key == 'h') port.write("G90\nG20\nG00 X0.000 Y0.000 Z0.000\n");
if (key == 'v') port.write("$0=75\n$1=74\n$2=75\n");
//if (key == 'v') port.write("$0=100\n$1=74\n$2=75\n");
if (key == 's') port.write("$3=10\n");
if (key == 'e') port.write("$16=1\n");
if (key == 'd') port.write("$16=0\n");
if (key == '0') openSerialPort();
if (key == 'p') selectSerialPort();
if (key == '$') port.write("$$\n");
}
if (!streaming && key == 'g') {
gcode = null; i = 0;
File file = null;
println("Loading file...");
selectInput("Select a file to process:", "fileSelected", file);
}
if (key == 'x') streaming = false;
}
void fileSelected(File selection) {
if (selection == null) {
println("Window was closed or the user hit cancel.");
} else {
println("User selected " + selection.getAbsolutePath());
gcode = loadStrings(selection.getAbsolutePath());
if (gcode == null) return;
streaming = true;
stream();
}
}
void stream()
{
if (!streaming) return;
while (true) {
if (i == gcode.length) {
streaming = false;
return;
}
if (gcode[i].trim().length() == 0) i++;
else break;
}
println(gcode[i]);
port.write(gcode[i] + '\n');
i++;
}
void serialEvent(Serial p)
{
String s = p.readStringUntil('\n');
println(s.trim());
if (s.trim().startsWith("ok")) stream();
if (s.trim().startsWith("error")) stream(); // XXX: really?
}
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