longSW.ino

#define SW1 A0

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(SW1, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  if (digitalRead(SW1)) {
    long StartMS = millis();
    bool longSW = false;
    while(digitalRead(SW1)) {
      if (millis() - StartMS > 5000) longSW = true;
    }
    Serial.println(longSW);
  }
}