Another button debouncer v1000000.0

/*
   April 6, 2019
   Button demonstration:
   1. The button sends messages only when it changes state, holding it down does nothing.
   2. Pin #13 LED lights up to reflect the button state.
   3. The button uses non-blocking button debouncing on both the press and the release events.
   Board = any

   Turn on the serial monitor to use this sketch. After the "Exiting setup()" message, the button sends a serial message every time it is pressed down, and every time it is released.

*/


int button_1_pin = 7; // This is where the button is connected.
// The above pin is using INPUT_PULLUP, so it should connect to a ground pin when pressed.

int button_debounce_time = 100; // This is the time in milliseconds to wait, to prevent the buttons from bouncing.

// The variables above you can change the values of.
// @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
// The variables below do not change the values of.

int button_1_previous_state = 0;
int button_1_current_state = 0;

bool buttons_enabled = true;
unsigned long button_press_begin_time = 0;
unsigned long button_press_current_time = 0;



void setup() {
  Serial.begin(9600);
  pinMode(button_1_pin, INPUT_PULLUP);
  Serial.println("Exiting setup()");
}



void loop() {

  if (buttons_enabled == true) {
    button_1_current_state = 0;
    if (digitalRead(button_1_pin) == LOW) {
      button_1_current_state = 1;
    }
    // The if() condditions below make sure that you only get the "button pressed" message when the button state changes from "off" to "on".
    if (button_1_previous_state == 0) { // If the button was previously not pressed...
      if (button_1_current_state == 1) { // ...but it is pressed now...
        Serial.println("Button pressed.");
        digitalWrite(13, HIGH);
        button_pressed();
      }
    }
    // The two lines below place a de-bounce delay when the button is released, to make sure that it does not trigger a positive pulse at that time.
    // This part can be placed inside the "if (buttons_enabled == true)" condition because the only time that digitalRead() is called on the button pin is read is when buttons_enabled == true.
    if (button_1_previous_state == 1) { // If the button was previously being pressed...
      if (button_1_current_state == 0) { // ...but it is not pressed now...
        Serial.println("Button released.");
        digitalWrite(13, LOW);
        button_pressed();
      }
    }
    button_1_previous_state = button_1_current_state;
  }

  else { // If the buttons are not enabled, then that means they are de-bouncing and the elapsed time since the press must be checked.
    button_press_current_time = millis();
    if (button_press_current_time > button_press_begin_time) {
      if (button_press_current_time >= (button_press_begin_time + button_debounce_time)) {
        buttons_enabled = true;
      }
    }
    else {
      button_press_begin_time = millis();
    }
  }

} // end of main loop()


void button_pressed() {
  buttons_enabled = false;
  button_press_begin_time = millis();
}