PCB word clock

Update fun fact: analyzing a charlie plexed matrix for bugs is so much easier when the LEDs are upside down - because of the markings :)

I finally got my LEDs and took the time to hand solder a PCB :) it bleeds a bit in the picture, but in real life it's quite good. The code so far is only a mock up, but there is scanning and matrix stuff involved already.

#include <avr/pgmspace.h>

const int leds[]  = {2,3,4,5,6,7,8,9,10,11,12,13};

const int matrix[10][11][2]  = {
  {  {1, 0},  {0, 1},  {0, 2},  {0, 3},  {0, 4},  {0, 5},  {0, 6},  {0, 7},  {0, 8},  {0, 9}, {0, 10} }, // 0
  {  {2, 0},  {2, 1},  {1, 2},  {1, 3},  {1, 4},  {1, 5},  {1, 6},  {1, 7},  {1, 8},  {1, 9}, {1, 10} }, // 1
  {  {3, 0},  {3, 1},  {3, 2},  {2, 3},  {2, 4},  {2, 5},  {2, 6},  {2, 7},  {2, 8},  {2, 9}, {2, 10} }, // 2
  {  {4, 0},  {4, 1},  {4, 2},  {4, 3},  {3, 4},  {3, 5},  {3, 6},  {3, 7},  {3, 8},  {3, 9}, {3, 10} }, // 3
  {  {5, 0},  {5, 1},  {5, 2},  {5, 3},  {5, 4},  {4, 5},  {4, 6},  {4, 7},  {4, 8},  {4, 9}, {4, 10} }, // 4
  {  {6, 0},  {6, 1},  {6, 2},  {6, 3},  {6, 4},  {6, 5},  {5, 6},  {5, 7},  {5, 8},  {5, 9}, {5, 10} }, // 5
  {  {7, 0},  {7, 1},  {7, 2},  {7, 3},  {7, 4},  {7, 5},  {7, 6},  {6, 7},  {6, 8},  {6, 9}, {6, 10} }, // 6
  {  {8, 0},  {8, 1},  {8, 2},  {8, 3},  {8, 4},  {8, 5},  {8, 6},  {8, 7},  {7, 8},  {7, 9}, {7, 10} }, // 7
  {  {9, 0},  {9, 1},  {9, 2},  {9, 3},  {9, 4},  {9, 5},  {9, 6},  {9, 7},  {9, 8},  {8, 9}, {8, 10} }, // 8
  { {10, 0}, {10, 1}, {10, 2}, {10, 3}, {10, 4}, {10, 5}, {10, 6}, {10, 7}, {10, 8}, {10, 9}, {9, 10} } // 9
};

const boolean img [10][11] = {
  { true,  true, false,  true,  true, false,  true,  true,  true,  true, false},
  {false, false, false, false, false, false, false, false, false, false, false},
  {false, false, false, false, false, false, false, false, false, false, false},
  {false, false,  true,  true,  true,  true, false, false, false, false, false},
  {false, false, false, false,  true,  true,  true, false, false, false, false},
  {false, false, false, false, false, false, false, false, false, false, false},
  {false, false, false, false, false, false, false, false, false, false, false},
  {false, false, false, false, false, false, false, false, false, false, false},
  {false, false, false, false, false, false, false, false, false, false, false},
  {false, false, false, false,  true, false,  true,  true,  true,  true,  true},
};

void setup()  { }

void loop() {
    for (int y=0; y<10; y++) 
    {
      for (int x=0; x<11; x++) 
      {
        if (img[y][x]) charlie_matrix (x, y);
    }
  }
}

void charlie_matrix (int x, int y)
{
   int cx = matrix[y][x][0]; 
   int cy = matrix[y][x][1]; 
  
  digitalWrite(leds[cx], LOW);
  pinMode(leds[cx], OUTPUT);
  digitalWrite(leds[cy], HIGH);
  pinMode(leds[cy], OUTPUT);
  delayMicroseconds(65);

  pinMode(leds[cx], INPUT);
  digitalWrite(leds[cx], LOW);
  pinMode(leds[cy], INPUT);
  digitalWrite(leds[cy], LOW);
  
  delayMicroseconds(5);
}

Since someone on twitter pointed out that the project documentation is an epicfail, I felt compelled to edit the details and add informations on charlieplexing and the general idea. I first was a bit annoyed, but mostly because the entity was right :) I tend to not document my projects very well, mostly because it's easier to write about it afterwards and laziness. Now it feels more complete though.

So for science I've also added the german layout and ordered this one on 0.8mm boards.