#include <math.h>
#include "neopixel.h"

#define PIXEL_COUNT 24
#define PIXEL_PIN D2
#define PIXEL_TYPE WS2812

Adafruit_NeoPixel strip(PIXEL_COUNT, PIXEL_PIN, PIXEL_TYPE);

const int x_out = A1; /* connect x_out of module to A1 of Particle Photon board */
const int y_out = A2; /* connect y_out of module to A2 of Particle Photon board */
const int z_out = A3; /* connect z_out of module to A3 of Particle Photon board */
const int buzzer_pin = D0;
const int button_pin = D3;
unsigned long last_time = 0;
unsigned long current_time = 0;
int state = 0;
int bed_condition = 1;
int count = 0;
double prior_y_g_value = 0.0;
double y_change;
double prior_x_g_value = 0.0;
double x_change;
double prior_z_g_value = 0.0;
double z_change;
int brightness;

void setup() {
  Serial.begin(9600);
  Particle.subscribe("justgotinbedmyhomie", my_handler_inbed);
  Particle.subscribe("justgotoutofbedfool", my_handler_outbed);
  pinMode(buzzer_pin, OUTPUT);
  pinMode(button_pin, INPUT_PULLUP);
  strip.begin();
  strip.show();
}

void loop() {
  int x_adc_value, y_adc_value, z_adc_value;
  double x_g_value, y_g_value, z_g_value, sum_g_value, delta_g_value;
  double roll, pitch, yaw;
  x_adc_value = analogRead(x_out); /* Digital value of voltage on x_out pin */
  y_adc_value = analogRead(y_out); /* Digital value of voltage on y_out pin */
  z_adc_value = analogRead(z_out); /* Digital value of voltage on z_out pin */

  x_g_value = ( ( ( (double)(x_adc_value * 3.3)/4095) - 1.65 ) / 0.330 ); /* Acceleration in x-direction in g units */
  y_g_value = ( ( ( (double)(y_adc_value * 3.3)/4095) - 1.65 ) / 0.330 ); /* Acceleration in y-direction in g units */
  z_g_value = ( ( ( (double)(z_adc_value * 3.3)/4095) - 1.65 ) / 0.330 ); /* Acceleration in z-direction in g units */
  y_change = y_g_value - prior_y_g_value; //Calculate the change of g value in y axis
  prior_y_g_value = y_g_value;
  x_change = x_g_value - prior_x_g_value; //Calculate the change of g value in x axis
  prior_x_g_value = x_g_value;
  z_change = z_g_value - prior_z_g_value; //Calculate the change of g value in x axis
  prior_z_g_value = z_g_value;

  sum_g_value = sqrt(pow(x_g_value,2) + pow(y_g_value,2) + pow(z_g_value,2)); //The sum of the square of x_g_value, y_g_value, z_g_value
  delta_g_value = sqrt(pow(x_change,2) + pow(y_change,2) + pow(z_change,2));
 //print in the Serial
  Serial.print("x = ");
  Serial.print(x_g_value);
  Serial.print("\t\t");
  Serial.print("y = ");
  Serial.print(y_g_value);
  Serial.print("\t\t");
  Serial.print("z = ");
  Serial.print(z_g_value);
  Serial.print("\t\t");
  Serial.print("sum_g_value = ");
  Serial.print(sum_g_value);
  Serial.print("\t\t");
  Serial.print("delta_g_value = ");
  Serial.print(delta_g_value);
  Serial.print("\t\t");

  // Serial.print("x_change = ");
  // Serial.print(fabs(x_change));
  // Serial.print("\t\t");
  // Serial.print("y_change = ");
  // Serial.print(fabs(y_change));
  // Serial.print("\t\t");
  // Serial.print("z_change = ");
  // Serial.print(fabs(z_change));
  // Serial.print("\t\t");
  // delay(100);

  roll = ( ( (atan2(y_g_value,z_g_value) * 180) / 3.14 ) + 180 ); /* Formula for roll */
  pitch = ( ( (atan2(z_g_value,x_g_value) * 180) / 3.14 ) + 180 ); /* Formula for pitch */
  //yaw = ( ( (atan2(x_g_value,y_g_value) * 180) / 3.14 ) + 180 ); /* Formula for yaw */
  /* Not possible to measure yaw using accelerometer. Gyroscope must be used if yaw is also required */

  Serial.print("Roll = ");
  Serial.print(roll);
  Serial.print("\t");
  Serial.print("Pitch = ");
  Serial.print(pitch);
  Serial.print("\n\n");
  delay(100);

  if(digitalRead(button_pin) == LOW){
    count = 0;
  }

  if(bed_condition == 1){
    if (digitalRead(button_pin) == LOW){//press the button to stop the buzzer and reset the system
      noTone(buzzer_pin);
      count = 0;
      state = 0;
    }

    //detect whether there is a fall or not, state == 0 means current there is no fall detected   && position_detector(x_change, y_change, z_change)==1
    else if(delta_g_value > 3.5 && state == 0 ){
        delay(1000);

        x_adc_value = analogRead(x_out); /* Digital value of voltage on x_out pin */
        y_adc_value = analogRead(y_out); /* Digital value of voltage on y_out pin */
        z_adc_value = analogRead(z_out); /* Digital value of voltage on z_out pin */

        x_g_value = ( ( ( (double)(x_adc_value * 3.3)/4095) - 1.65 ) / 0.330 ); /* Acceleration in x-direction in g units */
        y_g_value = ( ( ( (double)(y_adc_value * 3.3)/4095) - 1.65 ) / 0.330 ); /* Acceleration in y-direction in g units */
        z_g_value = ( ( ( (double)(z_adc_value * 3.3)/4095) - 1.65 ) / 0.330 );

        roll = ( ( (atan2(y_g_value,z_g_value) * 180) / 3.14 ) + 180 ); /* Formula for roll */
        pitch = ( ( (atan2(z_g_value,x_g_value) * 180) / 3.14 ) + 180 ); /* Formula for pitch */
        Serial.println(roll);
        Serial.println(pitch);

        if(position_detector(roll, pitch) == 1){
          Serial.println("fall detected");
          state = 1;
          buzzer();
        }

      }



    else if(state == 1 ){//state == 1 means there is already a fall detected
      Serial.println("signal has been sent");
      publish_event();
      tone(buzzer_pin, 2000);
      delay(500);
      noTone(buzzer_pin);
      delay(2500);
    }
}
delay(100);
}

void publish_event(){
  current_time = millis();
  if (current_time - last_time >= 30000){
    Particle.publish("has/fall_detector");
    last_time = current_time;
  }
}

//handle the event that someone gets is bed, turn off the system
void my_handler_inbed(const char *event, const char *data){
  Serial.println("gotinbed");
  bed_condition = 0;
}

//hanlde the event that someone gets out of bed, turn on the system
void my_handler_outbed(const char *event, const char *data){
  Serial.println("gotoutofbed");
  bed_condition = 1;
}

//function to detect the g-change of three axis
bool position_detector(double roll, double pitch){
  if( roll>150 && roll<190 ){
    if( pitch>240 && pitch<300){
      return 0;
    }
  }
  else{
    return 1;
  }
}

//function for buzzer to ring
void buzzer(){
  while (digitalRead(button_pin) == HIGH && count < 10){
    tone(buzzer_pin, 2000);
    delay(500);
    Serial.println(count);
    count ++;
  }

  if (digitalRead(button_pin) == LOW){
    noTone(buzzer_pin);
    count = 0;
  }

  else if (count >= 10){
    state = 1;
  }
}

void breathing(){
  for(int num=0;num<strip.numPixels()-1;num++){
    strip.setColorDimmed(num, 255, 0, 0, int(brightness));
  }

  for(double t=0.0;t<2000;t++){
    brightness = sin(t)*200;
  }
}
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