Fitbody

#include <Wire.h>
#include <Adafruit_MMA8451.h>
#include <Adafruit_Sensor.h>
#include <math.h>
#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>

// --- Sensor Initialization ---
Adafruit_MMA8451 mma = Adafruit_MMA8451();
#define RED_LED_PIN 25
#define IR_LED_PIN 26
#define PHOTO_DIODE_PIN 34

// --- BLE Configuration ---
#define SERVICE_UUID        "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"
BLEServer* pServer = NULL;
BLECharacteristic* pCharacteristic = NULL;
bool deviceConnected = false;

void setup() {
  Serial.begin(115200);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(IR_LED_PIN, OUTPUT);
  pinMode(PHOTO_DIODE_PIN, INPUT);
  
  if (!mma.begin()) {
    Serial.println("Error: MMA8451 not detected");
    while (1);
  }
  mma.setRange(MMA8451_RANGE_2_G);
  
  // --- BLE Initialization ---
  BLEDevice::init("ESP32_Sensor");
  pServer = BLEDevice::createServer();
  pCharacteristic = pServer->createService(SERVICE_UUID)->createCharacteristic(
                      CHARACTERISTIC_UUID,
                      BLECharacteristic::PROPERTY_READ | BLECharacteristic::PROPERTY_NOTIFY
                    );
  pCharacteristic->addDescriptor(new BLE2902());
  pServer->start();
  BLEDevice::getAdvertising()->addServiceUUID(SERVICE_UUID);
  BLEDevice::getAdvertising()->start();
}

void loop() {
  sensors_event_t event;
  mma.getEvent(&event);
  float norm = sqrt(event.acceleration.x * event.acceleration.x +
                     event.acceleration.y * event.acceleration.y +
                     event.acceleration.z * event.acceleration.z);
  
  float spO2 = measureSpO2();
  
  String data = "Acc: " + String(norm) + " m/s2, SpO2: " + String(spO2) + "%";
  pCharacteristic->setValue(data.c_str());
  pCharacteristic->notify();
  delay(500);
}

float measureSpO2() {
  digitalWrite(RED_LED_PIN, HIGH);
  digitalWrite(IR_LED_PIN, LOW);
  delay(5);
  int redValue = analogRead(PHOTO_DIODE_PIN);

  digitalWrite(RED_LED_PIN, LOW);
  digitalWrite(IR_LED_PIN, HIGH);
  delay(5);
  int irValue = analogRead(PHOTO_DIODE_PIN);
  
  return 110 - 25 * (redValue / (float)irValue);
}