Creating Images Using One LED

//Bitmap reading function partially from Adafruit

#include <SD.h>
#include <SPI.h>
#include "DRV8825.h"

#define MOTOR_STEPS 200
#define RPM 150
#define MICROSTEPS 4

//pin definitions
#define STEPPER_X_DIR 7
#define STEPPER_X_STEP 6
#define STEPPER_X_EN 8
#define STEPPER_Y_DIR 4
#define STEPPER_Y_STEP 5
#define STEPPER_Y_EN 12

#define X 0
#define Y 1

#define X_DIR_FLAG -1 //1 or -1 to flip direction
#define Y_DIR_FLAG 1 //1 or -1 to flip direction

#define STEPS_PER_MM (3.75 * MICROSTEPS) //steps needed to move 1mm
#define SPACE_BETWEEN_POSITIONS 5 //5mm per move

#define R A0
#define G A1
#define B A2

#define SD_CS 22

int currentPositions[] = {0, 0};

DRV8825 stepperX(MOTOR_STEPS, STEPPER_X_DIR, STEPPER_X_STEP, STEPPER_X_EN);
DRV8825 stepperY(MOTOR_STEPS, STEPPER_Y_DIR, STEPPER_Y_STEP, STEPPER_Y_EN);

void setup() {
  Serial.begin(115200);
  init_steppers();
  SD.begin(SD_CS);
  createBitmaps();
  stepperX.disable();
  stepperY.disable();
  while(1);
}

void loop() {
}

void createBitmaps(){
  File dir = SD.open("bitmaps");
  while(true){
    File bitmap = dir.openNextFile();
    if(!bitmap){
      break;
    }
    paintBitmap(bitmap);
    delay(15000);
  }
  
}

#define BUFFPIXEL 20
void paintBitmap(File bmpFile){
  int bmpWidth, bmpHeight;
  uint8_t bmpDepth;
  uint32_t bmpImageOffset;
  uint32_t rowSize;               // Not always = bmpWidth; may have padding
  uint8_t  sdbuffer[3 * BUFFPIXEL]; // pixel buffer (R+G+B per pixel)
  uint8_t  buffidx = sizeof(sdbuffer); // Current position in sdbuffer
  boolean  goodBmp = false;       // Set to true on valid header parse
  boolean  flip = true;        // BMP is stored bottom-to-top
  int      w, h, row, col;
  uint8_t  r, g, b;
  uint32_t pos = 0, startTime = millis();

  Serial.println();
  Serial.print("Loading image '");
  Serial.print(bmpFile.name());
  Serial.println('\'');

  // Open requested file on SD card

  // Parse BMP header
  if (read16(bmpFile) == 0x4D42) { // BMP signature
    Serial.print("File size: "); Serial.println(read32(bmpFile));
    (void)read32(bmpFile); // Read & ignore creator bytes
    bmpImageOffset = read32(bmpFile); // Start of image data
    Serial.print("Image Offset: "); Serial.println(bmpImageOffset, DEC);
    // Read DIB header
    Serial.print("Header size: "); Serial.println(read32(bmpFile));
    bmpWidth = read32(bmpFile);
    bmpHeight = read32(bmpFile);
    if (read16(bmpFile) == 1) { // # planes -- must be '1'
      bmpDepth = read16(bmpFile); // bits per pixel
      Serial.print("Bit Depth: "); Serial.println(bmpDepth);
      if ((bmpDepth == 24) && (read32(bmpFile) == 0)) { // 0 = uncompressed

        goodBmp = true; // Supported BMP format -- proceed!
        Serial.print("Image size: ");
        Serial.print(bmpWidth);
        Serial.print('x');
        Serial.println(bmpHeight);

        // BMP rows are padded (if needed) to 4-byte boundary
        rowSize = (bmpWidth * 3 + 3) & ~3;

        // If bmpHeight is negative, image is in top-down order.
        // This is not canon but has been observed in the wild.
        if (bmpHeight < 0) {
          bmpHeight = -bmpHeight;
          flip = false;
        }

        // Crop area to be loaded
        w = bmpWidth;
        h = bmpHeight;

        if(bmpWidth*bmpHeight>290){ //Too large
          Serial.println("File is too large to be printed.");
          return;
        }
        
        for(uint8_t i=0; i<5;i++){
          analogWrite(R, 150);
          delay(500);
          analogWrite(R, 0);
          delay(500);
        }
        for (row = 0; row<h; row++) { // For each scanline...
          moveToPosition(0, row);
          // Seek to start of scan line.  It might seem labor-
          // intensive to be doing this on every line, but this
          // method covers a lot of gritty details like cropping
          // and scanline padding.  Also, the seek only takes
          // place if the file position actually needs to change
          // (avoids a lot of cluster math in SD library).
          if (flip) // Bitmap is stored bottom-to-top order (normal BMP)
            pos = bmpImageOffset + (bmpHeight - 1 - row) * rowSize;
          else     // Bitmap is stored top-to-bottom
            pos = bmpImageOffset + row * rowSize;
          if (bmpFile.position() != pos) { // Need seek?
            bmpFile.seek(pos);
            buffidx = sizeof(sdbuffer); // Force buffer reload
          }

          // optimize by setting pins now
          for (col = 0; col<w; col++) { // For each pixel...
                          // Time to read more pixel data?
            if (buffidx >= sizeof(sdbuffer)) { // Indeed
              bmpFile.read(sdbuffer, sizeof(sdbuffer));
              buffidx = 0; // Set index to beginning
            }

            // Convert pixel from BMP to TFT format, push to display
            b = sdbuffer[buffidx++];
            g = sdbuffer[buffidx++];
            r = sdbuffer[buffidx++];

            moveToPosition(col, row);
            activateLED(r,g,b);
            // optimized!
            //tft.pushColor(tft.Color565(r,g,b));
          } // end pixel
          analogWrite(R, 0);
          analogWrite(G, 0);
          analogWrite(B, 0);
        } // end scanline
        Serial.print("Loaded in ");
        Serial.print(millis() - startTime);
        Serial.println(" ms");
      } // end goodBmp
    }
  }

  bmpFile.close();
  moveToPosition(0,0);
  if (!goodBmp) Serial.println("BMP format not recognized.");
}

uint16_t read16(File f) {
  uint16_t result;
  ((uint8_t *)&result)[0] = f.read(); // LSB
  ((uint8_t *)&result)[1] = f.read(); // MSB
  return result;
}

uint32_t read32(File f) {
  uint32_t result;
  ((uint8_t *)&result)[0] = f.read(); // LSB
  ((uint8_t *)&result)[1] = f.read();
  ((uint8_t *)&result)[2] = f.read();
  ((uint8_t *)&result)[3] = f.read(); // MSB
  return result;
}

void activateLED(int r, int g, int b){
  Serial.print(F("LED has value of: "));
  Serial.print(r);
  Serial.print(", ");
  Serial.print(g);
  Serial.print(", ");
  Serial.println(b);
  analogWrite(R, r);
  analogWrite(G, g);
  analogWrite(B, b);
}

void moveToPosition(int x, int y){
  int newPosX = (x-currentPositions[X])*STEPS_PER_MM*X_DIR_FLAG*SPACE_BETWEEN_POSITIONS;
  int newPosY = (y-currentPositions[Y])*STEPS_PER_MM*Y_DIR_FLAG*SPACE_BETWEEN_POSITIONS;
  stepperX.move(newPosX);
  stepperY.move(newPosY);
  currentPositions[X] = x;
  currentPositions[Y] = y;
  Serial.print("Stepper positions: "); Serial.print(currentPositions[X]); Serial.print(", "); Serial.println(currentPositions[Y]);
}

void init_steppers(){
  stepperX.begin(RPM);
  stepperX.setEnableActiveState(LOW);
  stepperX.enable();
  stepperX.setMicrostep(MICROSTEPS);
  stepperY.begin(RPM);
  stepperY.setEnableActiveState(LOW);
  stepperY.enable();
  stepperY.setMicrostep(MICROSTEPS);
}