Button sticking?

Projects Programming
2

you have not set your LedStrip pins as output correctly

check when you initialize fadeStartTime

Depending on your Arduino, 13 is not the best pin to use for a button with INPUT_PULLUP

you should have another Boolean variable that you set to true when the button has been pushed and this is the one you test against to see if you call DoTheFade()

may be something like this (typed here, fully untested)

const byte LedStrip[] = {3, 5, 6};
const byte ButtonPin = 13; // suggest you take another one. 

const unsigned long FADE_PERIOD = 2000; // fade time is 2 seconds
unsigned long fadeStartTime;
bool fadingIsActive = false;

void setup() {
  for (byte i = 0; i < sizeof LedStrip; i++) pinMode(LedStrip[i], OUTPUT);
  pinMode (ButtonPin, INPUT_PULLUP);
}

void DoTheFade() {
  unsigned long progress = millis() - fadeStartTime;
  if (progress <= FADE_PERIOD) {
    // set the fading value 
    int brightness = map(progress, 0, FADE_PERIOD, 255, 0);
    for (byte i = 0; i < sizeof LedStrip; i++) analogWrite(LedStrip[i], brightness);
  } else {
    // we are done
    for (byte i = 0; i < sizeof LedStrip; i++) digitalWrite(LedStrip[i], LOW);
    fadingIsActive = false;
  }
}

void loop() {
  if ((digitalRead(ButtonPin) == LOW) && (!fadingIsActive)) {
    for (byte i = 0; i < sizeof LedStrip; i++) digitalWrite(LedStrip[i], HIGH);
    fadeStartTime = millis();
    fadingIsActive = true;
  }

  if (fadingIsActive) DoTheFade();
}

if all goes well (untested), at a press of a button the 3 LEDs (with current limiting resistors, right???) would turn on and start to fade until they go dark 2 second later. and if you press again, it starts again