Open fire on an LED matrix display

It is winter and the right time for warm thoughts. May this LED matrix open fire help.

Parts

• Arduino compatible Ultimate Starter Set*
• or an Arduino* (or compatible board*), Cables and an LED Matrix display with MAX7219*

Circuit

The LED matrix is connected directly to the Arduino. This requires three digital pins for SPI communication and two cables for the power supply (GND and 5V +).

You can find more information on how the LED matrix works in the Tutorials section: Arduino Matrix Display 8 × 8 pixels and lots of fun.

Code

Here is the program code. The light height of the individual rows is determined.

if (int(random(1)) == 0) {
    for (int x = 0; x < 8; x++) {
      theHeightTarget[x] = int(random(5)) + 1;
    }
  }

Then the program tries to adjust the current light height.

  // update
  for (int x = 0; x < 8; x++) {
    if (theHeightTarget[x] > theHeightCurrent[x])theHeightCurrent[x]++;
    if (theHeightTarget[x] < theHeightCurrent[x])theHeightCurrent[x]--;
  }

This is then shown on the matrix.

  // show display 
  for (int x = 0; x < 8; x++) {
    for (int y = 0; y < theHeightCurrent[x]; y++) {
      lc.setLed(0, x, y, 1);
    }
    for (int y = theHeightCurrent[x]; y < 8; y++) {
      lc.setLed(0, x, y, 0);
    }
  }

Every now and then a spark is released and flies upwards.

// sparks
  sparkX = int(random(8));
  if (int(random(40)) == 0) {
    for (int y = 4; y < 8; y++) {
      if (y == 4) {
        lc.setLed(0, sparkX, y, 1);
      } else {
        lc.setLed(0, sparkX, y, 1);
        lc.setLed(0, sparkX, y - 1, 0);
      }
      delay(25);
    }
  } else {
    delay(100);
  }

Find the complete code her:

#include "LedControl.h"
LedControl lc = LedControl(12, 11, 10, 1);

int theHeightTarget[8];
int theHeightCurrent[8];

int fireHeight = 0;
int sparkX = 0;

void setup() {
  lc.shutdown(0, false);
  lc.setIntensity(0, 8);
  lc.clearDisplay(0);
  Serial.begin(115200);
}

void loop() {  
  //lc.clearDisplay(0);
  // set Heights
  if (int(random(1)) == 0) {
    for (int x = 0; x < 8; x++) {
      theHeightTarget[x] = int(random(5)) + 1;
    }
  }

  // update
  for (int x = 0; x < 8; x++) {
    if (theHeightTarget[x] > theHeightCurrent[x])theHeightCurrent[x]++;
    if (theHeightTarget[x] < theHeightCurrent[x])theHeightCurrent[x]--;
  }

  // show display 
  for (int x = 0; x < 8; x++) {
    for (int y = 0; y < theHeightCurrent[x]; y++) {
      lc.setLed(0, x, y, 1);
    }
    for (int y = theHeightCurrent[x]; y < 8; y++) {
      lc.setLed(0, x, y, 0);
    }
  }

  // spark – Funkenflug
  sparkX = int(random(8));
  if (int(random(40)) == 0) {
    for (int y = 4; y < 8; y++) {
      if (y == 4) {
        lc.setLed(0, sparkX, y, 1);
      } else {
        lc.setLed(0, sparkX, y, 1);
        lc.setLed(0, sparkX, y - 1, 0);
      }
      delay(25);
    }
  } else {
    delay(100);
  }
}