#define MOTION_SENSOR_PIN 15
#define BUZZER_PIN        33
int motionStateCurrent = LOW;
int motionStatePrevious= LOW;

void setup(){
    Serial.begin(9600);
    pinMode(MOTION_SENSOR_PIN, INPUT);
    pinMode(BUZZER_PIN, OUTPUT);
}

void loop(){
    motionStatePrevious = motionStateCurrent;
    motionStateCurrent = digitalRead(MOTION_SENSOR_PIN);
    if(motionStatePrevious == LOW && motionStateCurrent == HIGH){
      Serial.println("Motion detected!, making sound");
      digitalWrite(BUZZER_PIN, HIGH);
    }
    else if(motionStatePrevious == HIGH && motionStateCurrent == LOW){
      Serial.println("Motion stopped!, stops making sound");
      digitalWrite(BUZZER_PIN, LOW);
    }
}