Two buttons with servos version 1.0

/*
   Two buttons with servos version 1.0

   This sketch assumes that you are using normally-open buttons connected directly to the arduino input pins,
   and are not using any pulldown resistors. The button pinmodes are declared as INPUT_PULLUP.

*/

#include <Servo.h>
Servo servo1;
Servo servo2;

int pushbutton_1_pin = 2; // this is the pin used for button #1
int button_1_state = 0; // this is where to store the pin state of button #1
int servo_1_pin = 3; // This is the PWM pin that servo #1 is connected to.
int servo_1_angles[] = {0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180}; // servo1 array
int servo_1_position = 0; // This is the array index for servo #1.
int servo_1_move_direction = 1; // 1 for ascending, -1 for descending

int pushbutton_2_pin = 4; // this is the pin used for button #2
int button_2_state = 0; // this is where to store the pin state of button #2
int servo_2_pin = 5; // This is the PWM pin that servo #2 is connected to.
int servo_2_angles[] = {0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180}; // servo2 array
int servo_2_position; // This is the array index for servo #2.
int servo_2_move_direction = 1; // 1 for ascending, -1 for descending

// Below are the variables used for button debouncing.
// This sketch uses a single debounce time for both buttons.
int button_debounce_time = 500; // This is the milliseconds time for button debouncing (the time delay after a button has been pressed).
unsigned long button_previous_time = 0;
unsigned long button_current_time = 0;
bool buttons_enabled = false; // This is a "switch" for enabling or disabling checks for button presses.

// When using C/C++ language, always declare your own functions before the main program functions.
// Some compilers will not give error messages but will compile incorrect runtime code if you don't do this!
void perform_button_1_function();
void perform_button_2_function();


void setup() {
  Serial.begin(9600);
  servo1.attach(servo_1_pin);
  servo1.write(0);
  servo2.attach(servo_2_pin);
  servo2.write(0);
  pinMode(pushbutton_1_pin, INPUT_PULLUP);
  pinMode(pushbutton_2_pin, INPUT_PULLUP);
}

void loop() {

  if (buttons_enabled == true) {

    // The section below is checking for a #1 button press.
    button_1_state = digitalRead(pushbutton_1_pin);
    if (button_1_state == LOW) {
      perform_button_1_function();
    }


    // The section below is the same as above, but for button #2 & servo #2.
    button_2_state = digitalRead(pushbutton_2_pin);
    if (button_2_state == LOW) {
      perform_button_2_function();
    }

  }
  else { // if buttons_enabled = false
    // If a button was pushed then this checks the time to see if the buttons should be re-enabled.
    button_current_time = millis();
    if (button_current_time >= button_previous_time) {
      if (button_current_time >= (button_previous_time + button_debounce_time)) {
        buttons_enabled = true;
      }
    }
    else {
      button_previous_time = millis(); // rollover condition for millis() time.
    }
  }

} // end of main loop



void perform_button_1_function() {
  servo_1_position = servo_1_position + servo_1_move_direction; // change to the new value if servo_1_position.
  // check that servo_1_position is still within the array index bounds (0 to 18).
  // change servo_1_position and servo_1_move_direction if servo_1_position has gone out of bounds.
  if (servo_1_position == 19) {
    servo_1_move_direction = -1;
    servo_1_position = 17;
  }
  if (servo_1_position == -1) {
    servo_1_move_direction = 1;
    servo_1_position = 0;
  }
  servo1.write(servo_1_angles[servo_1_position]);
  Serial.print("servo 1:");
  Serial.println(servo_1_angles[servo_1_position]);

  buttons_enabled = false; // disable any further button inputs (to debounce)
  button_previous_time = millis(); // start the debounce timer here
}



void perform_button_2_function() {
  servo_2_position = servo_2_position + servo_2_move_direction;
  if (servo_2_position == 19) {
    servo_2_move_direction = -1;
    servo_2_position = 17;
  }
  if (servo_2_position == -1) {
    servo_2_move_direction = 1;
    servo_2_position = 0;
  }
  servo1.write(servo_2_angles[servo_2_position]);
  Serial.print("servo 2:");
  Serial.println(servo_2_angles[servo_2_position]);

  buttons_enabled = false; // disable any further button inputs (to debounce)
  button_previous_time = millis(); // start the debounce timer here
}