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/*
Row-Column Scanning an 8x8 LED matrix with X-Y input
This example controls an 8x8 LED matrix using two analog inputs.
This example works for the Lumex LDM-24488NI Matrix. See
https://sigma.octopart.com/140413/datasheet/Lumex-LDM-24488NI.pdf
for the pin connections.
For other LED cathode column matrixes, you should only need to change the pin
numbers in the row[] and column[] arrays.
rows are the anodes
cols are the cathodes
---------
Pin numbers:
Matrix:
- digital pins 2 through 13,
- analog pins 2 through 5 used as digital 16 through 19
Potentiometers:
- center pins are attached to analog pins 0 and 1, respectively
- side pins attached to +5V and ground, respectively
created 27 May 2009
modified 30 Aug 2011
by Tom Igoe
This example code is in the public domain.
https://www.arduino.cc/en/Tutorial/BuiltInExamples/RowColumnScanning
*/
// 2-dimensional array of row pin numbers:
const int row[8] = {
2, 7, 19, 5, 13, 18, 12, 16
};
// 2-dimensional array of column pin numbers:
const int col[8] = {
6, 11, 10, 3, 17, 4, 8, 9
};
// 2-dimensional array of pixels:
int pixels[8][8];
// cursor position:
int x = 5;
int y = 5;
void setup() {
// initialize the I/O pins as outputs iterate over the pins:
for (int thisPin = 0; thisPin < 8; thisPin++) {
// initialize the output pins:
pinMode(col[thisPin], OUTPUT);
pinMode(row[thisPin], OUTPUT);
// take the col pins (i.e. the cathodes) high to ensure that the LEDS are off:
digitalWrite(col[thisPin], HIGH);
}
// initialize the pixel matrix:
for (int x = 0; x < 8; x++) {
for (int y = 0; y < 8; y++) {
pixels[x][y] = HIGH;
}
}
}
void loop() {
// read input:
readSensors();
// draw the screen:
refreshScreen();
}
void readSensors() {
// turn off the last position:
pixels[x][y] = HIGH;
// read the sensors for X and Y values:
x = 7 - map(analogRead(A0), 0, 1023, 0, 7);
y = map(analogRead(A1), 0, 1023, 0, 7);
// set the new pixel position low so that the LED will turn on in the next
// screen refresh:
pixels[x][y] = LOW;
}
void refreshScreen() {
// iterate over the rows (anodes):
for (int thisRow = 0; thisRow < 8; thisRow++) {
// take the row pin (anode) high:
digitalWrite(row[thisRow], HIGH);
// iterate over the cols (cathodes):
for (int thisCol = 0; thisCol < 8; thisCol++) {
// get the state of the current pixel;
int thisPixel = pixels[thisRow][thisCol];
// when the row is HIGH and the col is LOW,
// the LED where they meet turns on:
digitalWrite(col[thisCol], thisPixel);
// turn the pixel off:
if (thisPixel == LOW) {
digitalWrite(col[thisCol], HIGH);
}
}
// take the row pin low to turn off the whole row:
digitalWrite(row[thisRow], LOW);
}
}
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