22. Matrix LED

This lesson uses: Arduino UNO R3 board, TinkerBlock TK52 Matrix LED module, jumper wires (or breadboard). Learn to control the 8×8 matrix with LedControl library and arrays; outcome: matrix shows a heart pattern for about 1 s, then clears, repeat.

1. Install the library

Before writing code, install the LedControl library:

1. Arduino IDE: Tools → Manage Libraries...
2. Search: LedControl
3. Find LedControl by Eberhard Fahle, click Install
4. Wait until installation finishes

2. Wiring

Connect TK52 Matrix LED to Arduino:

• GND → Arduino GND
• VCC → Arduino 5V
• DIN → Arduino D3
• CLK → Arduino D4
• CS → Arduino D2
• NC leave unconnected

3. New sketch

1. Arduino IDE: File → New (or Ctrl/Cmd + N) to create a blank sketch
2. Confirm board and port are selected (same as Lesson 01)
3. Type the code below into the file top and into setup() and loop() yourself

4. Program structure

Same as last lesson: two fixed blocks setup() and loop().

• setup(): Include library, create display object, init matrix; runs once.
• loop(): Keep repeating “show pattern → wait → show next → repeat”.

Type the code below and the matrix will show a heart—that’s how 8×8 works.

5. Code to write

Type the code below at the top of the file and in setup() and loop() (do not copy-paste; typing it yourself helps you remember):

#include <LedControl.h>

#define DIN_PIN 3   // DIN on D3
#define CLK_PIN 4   // CLK on D4
#define CS_PIN 2    // CS on D2

LedControl lc = LedControl(DIN_PIN, CLK_PIN, CS_PIN, 1);

void setup() {
  lc.shutdown(0, false);   // Wake matrix
  lc.setIntensity(0, 8);   // Brightness 0-15
  lc.clearDisplay(0);      // Clear screen
}

void loop() {
  // Heart pattern
  byte heart[8] = {
    0b00000000,
    0b01100110,
    0b11111111,
    0b11111111,
    0b01111110,
    0b00111100,
    0b00011000,
    0b00000000
  };
  
  for (int i = 0; i < 8; i++) {
    lc.setRow(0, i, heart[i]);   // Write row i (0 = first block)
  }
  delay(1000);   // Show 1 s
  lc.clearDisplay(0);   // Clear matrix
  delay(500);   // 0.5 s before repeat
}

Program notes

Overall idea: 8×8 matrix has 8 points per row; 8 bytes = 8 rows, bit 1=on, 0=off; binary 0b... is convenient. Library talks to MAX7219 via DIN, CLK, CS; setRow(0, row, data) sets one row, clearDisplay(0) clears. A for loop writes the 8 rows of heart[] to show the pattern.

6. Hands-on

1. After entering the code, click Verify (✓) to compile
2. Click Upload (→) to upload to the board
3. Watch TK52: heart pattern, then clear, repeat
4. Try yourself: change the pattern data to make your own shape

Expected result: As in the figure.

Note: If your kit has TK53 74HC595 Segment LED, you can try it on your own.

Proceed to Lesson 23.

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