Digital Input - Pushbutton - Pull Up / Pull Down Resistors

/* 
    button_debounce_pullup.ino

    Manages the debounce of a pushbutton or switch connected to a pullup resistor. 
*/

int pinLED = 5; 
int pinPushButtonPullUp = 6;
int buttonState = HIGH;     // buttonState & lastButtonState are initialized for a pullup resistor         
int lastButtonState = HIGH;
unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled
unsigned long debounceDelay = 50;    // The switch debounce time.  50 to 100 ms

void setup() {

  pinMode(pinLED, OUTPUT);
  pinMode(pinPushButtonPullUp, INPUT);

  blinkLED(pinLED);
  
}   // setup()


void loop() {

  // Detect a change in the pushbutton state.
  // This logic is for a button using a pullup resistor. 
  buttonState = digitalRead(pinPushButtonPullUp); 
  // if millis() or timer wraps around, reset it
  if (lastDebounceTime > millis())  lastDebounceTime = millis();
  if (buttonState != lastButtonState) { 
    // Multiple changes in the buttonState can occur when a pushbutton is 
    // pressed, or a switch is toggled. Use a debounce timer to only react
    // to a change in button state after an interval of debounceDelay. 
    lastButtonState = buttonState;
    //  Check if enough time has passed to evaluate another pushbutton press.
    if ((millis() - lastDebounceTime) > debounceDelay) {
      lastDebounceTime = millis();
      if (buttonState == LOW) {
          digitalWrite(pinLED, HIGH);
      } else {
          digitalWrite(pinLED, LOW);
      } // buttonState
    } // millis()
  } // buttonState != lastButtonState

}   // loop()



void blinkLED(byte ledPIN){
  //  consumes 300 ms.
  for(int i = 5; i>0; i--){
    digitalWrite(ledPIN, HIGH);
    delay(30);
    digitalWrite(ledPIN, LOW);
    delay(30);
  }    
} // blinkLED()

 

/* 
    button_debounce_pulldown.ino

    Manages the debounce of a pushbutton or switch connected to a pulldown resistor. 
*/

int pinLED = 5; 
int pinPushButtonPullDown = 7;
int buttonState = LOW;     // buttonState & lastButtonState are initialized for a pulldown resistor         
int lastButtonState = LOW;
unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled
unsigned long debounceDelay = 50;    // The switch debounce time.  50 to 100 ms

void setup() {

  pinMode(pinLED, OUTPUT);
  pinMode(pinPushButtonPullDown, INPUT);

  blinkLED(pinLED);

}   // setup()


void loop() {
  
  // Detect a change in the pushbutton state.
  // This logic is for a button using a pulldown resistor. 
  buttonState = digitalRead(pinPushButtonPullDown); 
  // if millis() or timer wraps around, reset it
  if (lastDebounceTime > millis())  lastDebounceTime = millis();
  if (buttonState != lastButtonState) { 
    // Multiple changes in the buttonState can occur when a pushbutton is 
    // pressed, or a switch is toggled. Use a debounce timer to only react
    // to a change in button state after an interval of debounceDelay. 
    lastButtonState = buttonState;
    //  Check if enough time has passed to evaluate another pushbutton press.
    if ((millis() - lastDebounceTime) > debounceDelay) {
      lastDebounceTime = millis();
      if (buttonState == HIGH) {
          digitalWrite(pinLED, HIGH);
      } else {
          digitalWrite(pinLED, LOW);
      } // buttonState
    } // millis()
  } // buttonState != lastButtonState

}   // loop()



void blinkLED(byte ledPIN){
  //  consumes 300 ms.
  for(int i = 5; i>0; i--){
    digitalWrite(ledPIN, HIGH);
    delay(30);
    digitalWrite(ledPIN, LOW);
    delay(30);
  }    
} // blinkLED()

 

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