Microduino Dot Matrix Module Displays BMP Colored Image

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Outline

  • Extend the dot matrix screen wiki address and dot matrix library github adress
  • The new dot matrix library adds the function that let the dot matrix able to display bitmaps.
  • The previous bitmap function is limited to single-color bitmap, and needs to take modulus through module software, which is a little convenient.
  • The image format used now is BMP（full name is Bitmap）, which is the standard image file format in Windows operating system, and can display colored images.

Bill of Materials

  • Microduino Equipment
Module Number Function
Microduino-Core 1 Core board
Microduino-USBTTL 1 Program download
Microduino-Dot Matrix 4 To display
Microduino-Cube-S1 1 To extend

Principle of the Experiment

  • Typical BMP image file is composed of four parts:
    • Bitmap header file data structure. It contains information such as the type of BMP image file, and the displayed contents;
    • Bitmap information data structure. It contains information such as the width, height, and pressing method of BMP image, and the defined color.
    • Palette. This part is optional. Some bitmaps need palette, and some needn't, such as the true color image（24-bit BMP）.
    • Data of the bitmap. This part changes with the bit number of the BMP bitmap. Use RGB directlyin24-bit, and in other less than 24-bit ones, use the color index in the palette.

Because our dot matrix screen is 24-bit, it is natural that I add the bitmap displaying function as 24-bit BMP image. The function is：drawBMP(x,y,data). This function is transplanted on the basis of the spitftbitmap routine of Adafruit. It store the BMP images in Flash store, not occupying much memory space.

Program download

  • Please keep downloading and updating the latest Microduino official IDE.
  • Download the program from the link below: Dot-Matrix-BMP.ino

Operating Instructions

  • Step.1:
    • At first, let's find a small pictures of material.
    • You can find one in this wedsite：[1]
BMP1.jpg
  • Step.2:
    • Randomly choose one and save it.
    • Open it in drawing tool.
    • Save it as a 24-bit BMP image.
BMP2.jpg
BMP3.jpg


  • Step.3:
    • Download and open the tool：DataToHex
    • Open the BMP file that you saved.
    • After confirming the two items in the box are chosen correctly, click to generate array.
BMP4.jpg

BMP5.jpg


  • Step.4:
    • Then, open the generated TXT file of the same name in the BMP catalogue.
    • Copy the contents of the array.
    • Replace the content of BinCode array in the sample program.
    • Download your program to dot matrix（2x2 array）.
BMP6.jpg
BMP7.jpg

Programming

  • Stack Microduino-Core and [[Microduino-USBTTL] together.
    • Connect Microduino-USBTTL with USB cable and prepare to upload the program.
    • Note: You'd better upload the program before stacking all the modules.
  • Open Arduino IDE for Microduino environment. （Set-up reference: AVR Core: Getting Started）
  • Click 【Tool】, confirm board card （Microduino-Core） and processor（Atmega328P@16M,5V） are chosen correctly, and choose the corresponding port number(COMX).
  • Click 【File】->【Open】, browse to the project program address, and click "Dot-Matrix-BMP.ino" to open it.
  • After all these are correct, click "→" to download the program to the development board.

Code Instruction

#include "Microduino_Matrix.h" 
 
uint8_t Addr[MatrixPix_X][MatrixPix_Y] = { 
  { 64, 63}, 
  { 62, 61} cc
}; 
 
Matrix display = Matrix(Addr); 
 
static const uint8_t BinCode[] PROGMEM = { 
 
}; 
 
void setup(void) { 
  delay(6000); 
  Serial.begin(115200); 
 
  Wire.begin(); 
  display.clearDisplay(); 
  display.drawBMP(0, 0, BinCode); 
} 
 
void loop() { 
}

FAQ
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