Processing.org to Arduino thermal printing

[empwr]

Hi guys, I’m looking for some help on a project I have been working on. I am using Processing and Arduino in this project and have both sides working; I just need help linking the two together.

The idea is that an image is taken on Processing and is converted into a bitmap image. This image will be printed using a thermal printer on Arduino.

I have the camera working on Processing; it takes a b&w image (small enough for the printer), then converts it to a bitmap image and saves it ready to be printed. I have to manually upload the image to the Arduino sketch folder and run the code, which prints perfectly.

I need help with how to print the image directly after it has been taken. Is there a way to get Arduino to print this file straight away? I have looked into passing information through the serial, but I’m unsure how to pass a bitmap image this way and then print it. Any help on this would be much appreciated!!

Thank you in advance

Processing code:

Takes a 210x210 b&w image once a key is pressed, converts it to a bitmap and saves it as "imgTest.png"

import processing.video.*;

Capture cam;

int state = 0;

void setup() {
  size(210, 210);

  String[] cameras = Capture.list();
  cam = new Capture(this, cameras[1]);

  cam.start();
}

void draw() {
  if (cam.available() == true) {
    cam.read();
  }
  
    scale(-1, 1);
    image(cam, -width, height/150, width, height);
    //filter(GRAY);
    filter(THRESHOLD, 0.5);
}

void keyPressed() {
  
  saveFrame("imgTest.png");
  //selectInput("imgTest.png", "processImage");
  processImage();

}

void processImage() {
  String      filename, basename;
  PImage      img;
  PrintWriter output;
  int         pixelNum, byteNum, bytesOnLine = 99,
              x, y, b, rowBytes, totalBytes, lastBit, sum;
  println("Loading image...");
  filename = "imgTest.png";
  img      = loadImage("imgTest.png");

  // Morph filename into output filename and base name for data
  x = filename.lastIndexOf('.');
  if(x > 0) filename = filename.substring(0, x);  // Strip current extension
  x = filename.lastIndexOf('/');
  if(x > 0) basename = filename.substring(x + 1); // Strip path
  else      basename = filename;
  filename += ".h"; // Append '.h' to output filename
  println("Writing output to " + filename);

  // Calculate output size
  rowBytes   = (img.width + 7) / 8;
  totalBytes = rowBytes * img.height;
  // Convert image to B&W, make pixels readable
  img.filter(THRESHOLD);
  img.loadPixels();

  // Open header file for output (NOTE: WILL CLOBBER EXISTING .H FILE, if any)
  output = createWriter(filename); 

  // Write image dimensions and beginning of array
  output.println("#ifndef _" + basename + "_h_");
  output.println("#define _" + basename + "_h_");
  output.println();
  output.println("#define " + basename + "_width  " + img.width);
  output.println("#define " + basename + "_height " + img.height);
  output.println();
  output.print("static const uint8_t PROGMEM " + basename + "_data[] = {");

  // Generate body of array
  for(pixelNum=byteNum=y=0; y<img.height; y++) { // Each row...
    for(x=0; x<rowBytes; x++) { // Each 8-pixel block within row...
      lastBit = (x < rowBytes - 1) ? 1 : (1 << (rowBytes * 8 - img.width));
      sum     = 0; // Clear accumulated 8 bits
      for(b=128; b>=lastBit; b >>= 1) { // Each pixel within block...
        if((img.pixels[pixelNum++] & 1) == 0) sum |= b; // If black pixel, set bit
      }
      if(++bytesOnLine >= 10) { // Wrap nicely
          output.print("\n ");
          bytesOnLine = 0;
      }
      output.format(" 0x%02X", sum); // Write accumulated bits
      if(++byteNum < totalBytes) output.print(',');
    }
  }

  // End array, close file, exit program
  output.println();
  output.println("};");
  output.println();
  output.println("#endif // _" + basename + "_h_");
  output.flush();
  output.close();
  println("Done!");
  exit();
}

Arduino code:

Have to upload the "imgTest.png" image manually to the sketch folder, once uploaded it prints through the thermal printer

#include "imgTest.h"

#include "SoftwareSerial.h"
#define TX_PIN 6 // Arduino transmit  YELLOW WIRE  labeled RX on printer
#define RX_PIN 5 // Arduino receive   GREEN WIRE   labeled TX on printer

SoftwareSerial mySerial(RX_PIN, TX_PIN); // Declare SoftwareSerial obj first
Adafruit_Thermal printer(&mySerial);     // Pass addr to printer constructor

void setup() {

  mySerial.begin(19200);  // Initialize SoftwareSerial
  printer.begin();        // Init printer (same regardless of serial type)

  printer.printBitmap(imgTest_width, imgTest_height, imgTest_data);

  printer.feed(3);

  printer.sleep();      // Tell printer to sleep
  delay(3000L);         // Sleep for 3 seconds
  printer.wake();       // MUST wake() before printing again, even if reset
  printer.setDefault(); // Restore printer to defaults
}

void loop() {
}