/*
  Elderly free fall SOS

  NOTE : The fall is detected only when the value of all 
         the 3 axis is less than 0.3g
*/

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <MPU6050.h>

// Initialize LCD Display
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Initialize MPU6050 Accelerometer
MPU6050 mpu;

// Pin Definitions
#define buzzer_pin 3
#define led_pin 11
#define sosbutton_pin 12
#define l_led 13

void setup() {
  // Start Serial Communication
  //Serial.begin(9600);

  // Initialize LCD Display
  lcd.begin(16, 2); // 16 columns and 2 rows
  lcd.backlight();
  lcd.clear(); // Ensure LCD is clear
  lcd.setCursor(0, 0);
  lcd.print("Fall Detection");

  pinMode(l_led, OUTPUT);

  // Initialize MPU6050
  Wire.begin();
  mpu.initialize(); // Initialize MPU6050
  if (!mpu.testConnection()) {
    lcd.setCursor(0, 1);
    lcd.print("MPU Init Failed");
    while (1); // Stop if MPU6050 initialization fails
  }

  // Configure MPU6050
  mpu.setXAccelOffset(0); // Adjust offsets as necessary
  mpu.setYAccelOffset(0);
  mpu.setZAccelOffset(0);

  // Initialize Buzzer, LED, and Button
  pinMode(buzzer_pin, OUTPUT);
  pinMode(led_pin, OUTPUT);
  pinMode(sosbutton_pin, INPUT_PULLUP);

  lcd.setCursor(0, 1);
  lcd.print("System Ready");
  delay(2000);
  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("Monitoring...");
}

void loop() {
  // Read accelerometer values
  int16_t accelX = mpu.getAccelerationX();
  int16_t accelY = mpu.getAccelerationY();
  int16_t accelZ = mpu.getAccelerationZ();

  // Normalize accelerometer values (convert to g)
  float normAccelX = accelX / 16384.0; 
  float normAccelY = accelY / 16384.0;
  float normAccelZ = accelZ / 16384.0;

  // Detect fall based on sudden change in acceleration
  if (abs(normAccelX) < 0.3 && abs(normAccelY) < 0.3 && abs(normAccelZ) < 0.3) {
    triggerFallAlert();
  }

  // Check for manual SOS
  if (digitalRead(sosbutton_pin) == LOW) {
    triggerSOSAlert();
  }
}

// Function to handle fall alert
void triggerFallAlert() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Fall Detected!");
  lcd.setCursor(0, 1);
  lcd.print("Help Required");

  digitalWrite(buzzer_pin, HIGH); // Turn on buzzer
  for (int i = 0; i < 6; i++) { // Blink LED 6 times
    digitalWrite(led_pin, HIGH);
    delay(250);
    digitalWrite(led_pin, LOW);
    delay(250);
  }
  digitalWrite(buzzer_pin, LOW); // Turn off buzzer
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Monitoring...");
}

// Function to handle manual SOS
void triggerSOSAlert() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Manual SOS!");
  lcd.setCursor(0, 1);
  lcd.print("Help Required");

  digitalWrite(buzzer_pin, HIGH); // Turn on buzzer
  for (int i = 0; i < 6; i++) { // Blink LED 6 times
    digitalWrite(led_pin, HIGH);
    delay(250);
    digitalWrite(led_pin, LOW);
    delay(250);
  }
  digitalWrite(buzzer_pin, LOW); // Turn off buzzer
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Monitoring...");
}