// STM32 Blue Pill + PIR + HC-SR04 + Sound Sensor

// -------- Pin Definitions --------
#define PIR_PIN     PA5
#define TRIG_PIN    PA1
#define ECHO_PIN    PA2
#define SOUND_PIN   PB0

// Optional external LED
#define LED_PIN     PC13


void setup()
{
  Serial.begin(115200);

  pinMode(PIR_PIN, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(SOUND_PIN, INPUT);

  pinMode(LED_PIN, OUTPUT);

  digitalWrite(TRIG_PIN, LOW);

  Serial.println("System Started");
}


void loop()
{
  // =========================
  // 1. PIR SENSOR
  // =========================
  int motion = digitalRead(PIR_PIN);

  if (motion == HIGH)
  {
    Serial.println("Motion Detected!");

    // Blue Pill onboard LED is active LOW
    digitalWrite(LED_PIN, LOW);
  }
  else
  {
    Serial.println("No Motion");

    digitalWrite(LED_PIN, HIGH);
  }


  // =========================
  // 2. HC-SR04
  // =========================

  // Send trigger pulse
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);

  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);

  digitalWrite(TRIG_PIN, LOW);

  // Read echo
  long duration = pulseIn(ECHO_PIN, HIGH, 30000);

  float distance = duration * 0.0343 / 2;

  if (duration == 0)
  {
    Serial.println("Distance: Out of range");
  }
  else
  {
    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");
  }


  // =========================
  // 3. SOUND SENSOR
  // =========================

  int sound = digitalRead(SOUND_PIN);

  if (sound == HIGH)
  {
    Serial.println("Sound Detected!");
  }
  else
  {
    Serial.println("No Sound");
  }


  // =========================
  // Small delay
  // =========================
  delay(500);
}