Notes

Write a note in this a#include <Servo.h>
#include <AFMotor.h>

#define LINE_BUFFER_LENGTH 512

char STEP = MICROSTEP ;

// Servo position for Up and Down
const int penZUp = 95;
const int penZDown = 83;

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

// Should be right for DVD steppers, but is not too important here
const int stepsPerRevolution = 48;

// 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 = 0;
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 = 100.0;
float StepsPerMillimeterY = 100.0;

// 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(100);

// Decrease if necessary
myStepperX.setSpeed(600);

myStepperY.setSpeed(600);


// 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 ] = ''; // 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] = '';
buffer[1] = '';

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 = '';
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] = '';
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.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.");


}
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