/*
  Arduino | coding-help
  Nicole Thursday, May 14, 2026 10:14 PM
  hello everyone.
  i am working on a project with my arduino uno.
  it involves an mpu6050 and an OLED screen SSD1306.
  The code was made so that when the accelerometer is tilted,
  the screen says hello but I am a beginner and it will not work.
  each component works when tested separately but not together.
  the wired might be fried or the code because tbh i am not very
  familiar with C++ or this in general.
  id love if anyone can help plss i can send pictures in a second!
  this is the fried code and the fried wiring. pls if anyone know
  what might be wrong id appreciate it!
*/

#include <Wire.h>
#include <Servo.h>
#include <U8g2lib.h>
#include <Adafruit_MPU6050.h>
#include <Adafruit_Sensor.h>

// pin constants
const int BTN_PIN =  12;
const int BUZZ_PIN = 11;
const int RED_LED_PIN = 10;
const int GRN_LED_PIN =  9;
const int SERVO_PIN = 8;

// user constants
const int LOCKED_ANGLE = 0;
const int UNLOCK_ANGLE = 90;
const unsigned long ONE_SEC = 1000;

// global variables
// servo
int servo_locked = 1;
//button
int button_state;
int last_button_state = HIGH;
//double press thing
int press_count = 0;
long firstPressTime = 0;
long doublePressTime = 400;  //window
//wake-sleep
int system_awake = 0;
int tilt_threshold = 2;
unsigned long prevTime = 0;

// create objects
Servo lockServ;
Adafruit_MPU6050 mpu;
U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R2);

void move_servo() {
  if (servo_locked == 1) {
    lockServ.write(UNLOCK_ANGLE);
    servo_locked = 0;
    digitalWrite(RED_LED_PIN, LOW);
    digitalWrite(GRN_LED_PIN, HIGH);
  } else {
    lockServ.write(LOCKED_ANGLE);
    servo_locked = 1;
    digitalWrite(RED_LED_PIN, HIGH);
    digitalWrite(GRN_LED_PIN, LOW);
  }
}

void show_hello() {
  u8g2.firstPage();
  do {
    u8g2.setFont(u8g2_font_ncenB14_tr);
    u8g2.drawStr(0, 40, "HELLO");
  } while ( u8g2.nextPage() );
  delay(1000);
  u8g2.firstPage();
  do {
    u8g2.setFont(u8g2_font_ncenB10_tr);
    u8g2.drawStr(0, 20, "Please enter");
    u8g2.drawStr(0, 40, "your password");
  } while ( u8g2.nextPage() );
}

void sleep_everything() {
  lockServ.write(LOCKED_ANGLE);
  servo_locked = 1;
  press_count = 0;
  u8g2.clear();
}

void setup() {
  Wire.begin();
  Serial.begin(9600);

  u8g2.begin();
  u8g2.setFont(u8g2_font_ncenB10_tr);
  //u8g2.setFont(u8g2_font_ncenB14_tr);

  if (!mpu.begin()) {
    Serial.println(F("MPU6050 not found"));
    for (;;); // Don't proceed, loop forever
  }
  mpu.setAccelerometerRange(MPU6050_RANGE_8_G);
  mpu.setFilterBandwidth(MPU6050_BAND_21_HZ);

  pinMode(BTN_PIN, INPUT_PULLUP);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(GRN_LED_PIN, OUTPUT);
  pinMode(BUZZ_PIN, OUTPUT);
  lockServ.attach(SERVO_PIN);

  // initialize
  lockServ.write(LOCKED_ANGLE);
  digitalWrite(RED_LED_PIN, HIGH);
  u8g2.firstPage();
  do {
    u8g2.drawStr(0, 20, "Ready!");
  } while ( u8g2.nextPage() );
  Serial.println(F("Ready!"));
}

void loop() {

  //read accelerometer
  sensors_event_t a, g, temp;
  mpu.getEvent(&a, &g, &temp);
  //tilt i think help me
  int tilted = 0;
  if (a.acceleration.x > tilt_threshold) {
    tilted = 1;
  }
  if (a.acceleration.x < -tilt_threshold) {
    tilted = 1;
  }
  if (a.acceleration.y > tilt_threshold) {
    tilted = 1;
  }
  if (a.acceleration.y < -tilt_threshold) {
    tilted = 1;
  }

  if (millis() - prevTime >= ONE_SEC) {
    Serial.print("X: ");
    Serial.print(a.acceleration.x);
    Serial.print(" Y: ");
    Serial.print(a.acceleration.y);
    Serial.print(" Z: ");
    Serial.println(a.acceleration.z);
    Serial.print("Tilted: ");
    Serial.print(tilted);
    Serial.print("\tAwake: ");
    Serial.println(system_awake);
    Serial.println();
    prevTime = millis();
  }

  //screen wakes up
  if (tilted == 1 && system_awake == 0) {
    delay(300);
    system_awake = 1;
    show_hello();
  }

  // stay asleep or go to sleep
  if (tilted == 0 && system_awake == 1) {
    delay(500);
    system_awake = 0;
    sleep_everything();
  }

  //button works only when awake i think
  if (system_awake == 1) {
    button_state = digitalRead(BTN_PIN);

    if (last_button_state == HIGH && button_state == LOW) {
      press_count++;

      if (press_count == 1) {
        firstPressTime = millis();
      } else if (press_count == 2) {
        if (millis() - firstPressTime <= doublePressTime) {
          move_servo();
        } else {
          tone(BUZZ_PIN, 300, 400);
        }
        press_count = 0;
      }

      last_button_state = button_state;
      delay(100);
    }

    if (press_count == 1 && millis() - firstPressTime > doublePressTime) {
      press_count = 0;
      tone(BUZZ_PIN, 300, 400);  //if pressed one tone goes off logic
    }

    last_button_state = button_state;
  }
}