CODE issue of time controlling LED

Using Arduino Programming Questions
1

Hey guys,
I am a beginner of Arduino, I am now facing a problem that I want to use button to controll the numbers of LED depends on how many times I pushed the button. However, I also want to let the LED turn off every 10 sec. Which means, if I push the button 4 times, there will be 4 LEDs on, and after 10 seconds, there will be only 3 LEDs on etc. here is the code, but seems like it only works for the first LED, please give me some advices. Thank you!

const int buttonPin = 2;     // the number of the pushbutton pin
const int ledPin1 =  13;      // the number of the LED pin
const int ledPin2 =  12;
const int ledPin3 =  11;
const int ledPin4 =  10;
int i = 0;
// variables will change:
int buttonPushCounter = 0;   // counter for the number of button presses
int buttonState = 0;         // current state of the button
int lastButtonState = 0;

void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
  pinMode(ledPin4, OUTPUT);  
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT);     
  Serial.begin(9600);

}

void loop(){
  // read the pushbutton input pin:
  buttonState = digitalRead(buttonPin);

  // compare the buttonState to its previous state
  if (buttonState != lastButtonState) {
    // if the state has changed, increment the counter
    if (buttonState == HIGH) {
      // if the current state is HIGH then the button
      // wend from off to on:
      buttonPushCounter++;
      i++;

      Serial.println("on");
      Serial.print("number of button pushes:  ");
      Serial.println(buttonPushCounter, DEC);
    } 
    else{
      // if the current state is LOW then the button
      // wend from on to off:
      Serial.println("off"); 
i--;
delay(10000);
    }

}
  // save the current state as the last state, 
  //for next time through the loop
  lastButtonState = buttonState;

if (i==0){
    // turn LED off:
    digitalWrite(ledPin1, LOW); 
    digitalWrite(ledPin2, LOW);
    digitalWrite(ledPin3, LOW);
    digitalWrite(ledPin4, LOW);
  }

if (i==1){
      digitalWrite(ledPin1, HIGH); 
      digitalWrite(ledPin2, LOW);
      digitalWrite(ledPin3, LOW);
      digitalWrite(ledPin4, LOW);
      
}
if (i==2){
      digitalWrite(ledPin1, HIGH); 
      digitalWrite(ledPin2, HIGH); 
      digitalWrite(ledPin3, LOW);
      digitalWrite(ledPin4, LOW);
}
if (i==3){
      digitalWrite(ledPin1, HIGH); 
      digitalWrite(ledPin2, HIGH); 
      digitalWrite(ledPin3, HIGH); 
      digitalWrite(ledPin4, LOW);
}
if (i>=4){
      digitalWrite(ledPin1, HIGH); 
      digitalWrite(ledPin2, HIGH); 
      digitalWrite(ledPin3, HIGH); 
      digitalWrite(ledPin4, HIGH);
}

}
2

When delay() is called, nothing else happens. The program stops at that point until the specified time is elapsed. So no matter how many times you press the button after the first button press, your program STOPS for 10 seconds. After 10 seconds the next button press will result in something happening.

You placed your decrement and your delay() inside of the if-statement that checks for a change in button status. So you are only going to see the decrement whenever you press a button. Which probably means you increment and at the very end of the if statement you decrement, effectively doing nothing.

You will want to study the millis() function. It provides the capability to count time and decrement after X amount of time. It isn't a straight function call, but there are tons of examples on how to use it.

3

Thank you very much. I think i was wrong since I thought I am a beginner I should focus on what I have learned instead of looking for other things. But I think its time for me to get some new stuffs. :slight_smile: