Timer for how long button is not pressed

Question

I would like to timer for how long a button is not pressed. So actually if(buttonState == LOW 'for two seconds') than execute the code that comes after it. But the problem is while the user is still pressing the button the timer already starts.

Code:

int ledPin[] = {7,8,9,10};
int ledPin11 = 11;
long randNumber;
const int buttonPin = 2;
int buttonPushCounter = 0;
int buttonState = 0;
int lastButtonState = 0;
unsigned long previousMillis = 0;
const long interval = 2000;
void setup() {
 Serial.begin(9600);
 pinMode(LED_BUILTIN, OUTPUT);
 randomSeed(analogRead(0));
 randNumber = random(1, 16);
 Serial.println(randNumber);
 for (int i = 0; i < 4; i++) {
 pinMode(ledPin[i], OUTPUT);
 }
 pinMode(buttonPin, INPUT);
 }
 void loop() {
 displayBinary(randNumber); //functie 'display binary'
 unsigned long currentMillis = millis();
 if(currentMillis - previousMillis >= interval){
 previousMillis = currentMillis;
 if(buttonState == LOW){
 antwoord(buttonPushCounter,randNumber);
 delay(5000);
 displayBinary(randNumber);
 }
 }
 buttonState = digitalRead(buttonPin);
 if (buttonState != lastButtonState) { // als de button word ingedrukt krijgt buttonPushCounter + 1
 if (buttonState == HIGH) {
 buttonPushCounter++;
 Serial.print("Nummer hoe vaak is gedrukt");
 Serial.println(buttonPushCounter);
 } else {
 Serial.println("off");
}
delay(250);
 }
}
void antwoord(int teller, int antwoord) {
 if (teller == antwoord) {
 for (int i = 0; i < 4; i++) {
 pinMode(ledPin[i], LOW);
 }
 digitalWrite(LED_BUILTIN, HIGH);
 delay(250);
 digitalWrite(LED_BUILTIN, LOW);
 delay(250);
 digitalWrite(LED_BUILTIN, HIGH);
 delay(250);
 } else if (teller > antwoord || teller < antwoord) {
 for (int i = 0; i < 4; i++) {
 pinMode(ledPin[i], LOW);
 }
 digitalWrite(LED_BUILTIN, HIGH);
 }
}
void displayBinary(byte numToShow) //van byte naar decimaal
 {
 for (int i = 0; i < 4; i++) {
 if (bitRead(numToShow, i) == 1) {
 digitalWrite(ledPin[i], HIGH);
 } else {
 digitalWrite(ledPin[i], LOW);
 }
 }
 }

Answer 1

I would start a timer when the button changes state. Then you timeout if the button is released and it hasn't changed state for too long:

void loop()
{
 static int lastButtonState;
 static unsigned long buttonChangeTime;
 int buttonState = digitalRead(buttonPin);
 unsigned long now = millis();
 // Record time when button changes state.
 if (buttonState != lastButtonState)
 buttonChangeTime = now;
 // Timeout if button is not pushed for too long.
 if (buttonState == LOW && now - buttonChangeTime >= interval)
 Serial.println("Timeout.");
 lastButtonState = buttonState;
}

Don't forget to update lastButtonState on each iteration.

Answer 2

Your question is not clear enough.

I hope I get what you want.

Do while loop about the pressing...

if (button == LOW)
 while(!digitalread(button)){};

• aaa: Why the if? If it's true, the while won't continue, giving basically the same effect :)
• YoavShtainer: the if here is just if he want to do something before, is just habit.