Display countdown on 8x8 LED matrix

Using Arduino LEDs and Multiplexing
1

Hello,

I am trying to display a countdown on one 8x8 LED matrix (while motor is working for 30 seconds), but I can't get it to work. I mean the LED goes blank for 30 secs, but nothing is being scrolled.

Could someone give me a hint?

The code is following (I have been trying to use the assistance of ChatGDP):

void startMotorAndCountdown() {
  motorRunning = true;
  digitalWrite(relayPin, HIGH);  // Activate the relay to start the motor

  unsigned long countdownStartTime = millis();
  unsigned long countdownDuration = 30 * 1000;  // 30 seconds in milliseconds
  unsigned long lastUpdateTime = 0;
  const int updateInterval = 500;  // Update display every 500 milliseconds

  while (millis() - countdownStartTime <= countdownDuration) {
    // Calculate the remaining time
    unsigned long remainingTime = (countdownDuration - (millis() - countdownStartTime)) / 1000;

    // Update the display at a regular interval
    if (millis() - lastUpdateTime >= updateInterval) {
      myDisplay.displayClear();
      String buffer = String(remainingTime);  // Use String instead of char array
      myDisplay.displayText(buffer.c_str(), PA_LEFT, 50, 0, PA_SCROLL_LEFT);
      myDisplay.displayAnimate();  // Update the display
      lastUpdateTime = millis();   // Update last update time
    }

    // Add a small delay to avoid rapid updates
    delay(50);
  }

  digitalWrite(relayPin, LOW); // Deactivate the relay to stop the motor
  motorRunning = false;

  // Clear the display after the countdown is complete
  myDisplay.displayClear();
  myDisplay.displayText("AQQASHLARI TEMiZLE, CEMi 20 QEPiYE", PA_LEFT, 50, 0, PA_SCROLL_LEFT);
  myDisplay.displayAnimate();  // Update the display
}
2

Let's start by contacting a moderator and having the post moved to a thread of its own in a more appropriate topic.

1 Like
3

I have moved the posts to a dedicated topic as suggested.

Carry on.

2 Likes
4

MD parola does not like delays so if you need to take out the scroll or the delay
start with something simple just like trying to display one number

I also think you can use while instead of delay but I I'm not an expert lol

1 Like
5

Your comment near displayAnimate() seems to indicate that you expect the animation to happen when the function call is executed, somehow, in the background.

displayAnimate() will check to see if an animation frame is due and do something to animate if the time has come. Nothing will happen if there is no animation in progress.

The first displayAnimate() should be where you have the delay() and get rid of the delay().

The second displayAnimate() should be in your loop(). The way you have it structured at the end of your function it will do the first frame of the animation and then nothing else will happen.

Please read the documentation for the library (in docs folder) or look at how the examples have structured the animation.

1 Like
6

Thanks for help!
I've found a useful code piece that solved the problem.

void startMotorAndCountdown() {
  motorRunning = true;
  digitalWrite(relayPin, HIGH);  // Activate the relay to start the motor
  
  int counter = 30;      // the counter will start from 30, you can set any value
  char Buffer[3] = " ";  // create a buffer to hold the numbers
  unsigned long previousTime = 0;
  const unsigned long interval = 1000;  // interval at which to update the display (milliseconds)

  while (counter > 0) {
    unsigned long currentTime = millis();

    if (currentTime - previousTime >= interval) {
      previousTime = currentTime;
      
      myDisplay.displayClear();  // Clear the display before updating
      sprintf(Buffer, "%02d", counter);
      myDisplay.displayText(Buffer, PA_RIGHT, 0, 0, PA_PRINT);
      myDisplay.displayAnimate();  // Update the display

      counter--;
    }
  }

  digitalWrite(relayPin, LOW); // Deactivate the relay to stop the motor
  motorRunning = false;

  // Clear the display after the countdown is complete
  myDisplay.displayClear();
  myDisplay.displayText("AQQASHLARI TEMiZLE, CEMi 20 QEPiYE   ", PA_LEFT, 65, 0, PA_SCROLL_LEFT);
  myDisplay.displayAnimate();  // Update the display
}
7

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