Week 11 Production Assignment – Sci-Fi Sound Effects

For this assignment, my point of departure was to experiment with creating a sense of range and tonality with the buzzer as opposed to producing singular notes. I feel that the easiest two options would have been to do so by linking the frequency (pitch) produced by the buzzer to either a light sensor or an ultrasonic sensor. As we’ve seen in class, light is very difficult to control, so I opted for the latter.

As the input taken from the ultrasonic sensor updates quickly and at small increments, the sound produced by the buzzer becomes interestingly distorted and non-standard. To me, it suited the aesthetic of a suspenseful scene in a Sci-Fi thriller film. This led me to consider adding a more mechanical sound to complement the buzzer and create an almost chaotic result. To do this, I incorporated the use of a servo motor which varies the BPM of its 180 degree movement based on the same input taken from the ultrasonic sensor.

Ultimately, I enjoyed this assignment as it acts as an example that ideas can come naturally through experimentation. One aspect I feel could be developed is the application of the servo itself as I could potentially vary the surfaces that it rotates on (as briefly shown in the video) to produce different results.

Below is the code, a video of the circuit with just the buzzer and a video of the complete circuit.

#include <Servo.h>

const int trigPin = 9;
const int echoPin = 10;
const int buzzerPin = 11;
const int servoPin = 6;

Servo servoMotor;
int servoAngle = 0;
unsigned long previousServoTime = 0;
unsigned long servoInterval = 0;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
  servoMotor.attach(servoPin);
  Serial.begin(9600);
}

void loop() {
  // Send ultrasonic pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Measure the time it takes for the pulse to return
  long duration = pulseIn(echoPin, HIGH);

  // Calculate distance in centimeters
  float distance = duration * 0.034 / 2;

  // Map distance to BPM (Beats Per Minute)
  int bpm = map(distance, 0, 100, 100, 200);

  // Move the servo motor back and forth
  unsigned long currentMillis = millis();
  if (currentMillis - previousServoTime >= servoInterval) {
    servoMotor.write(servoAngle);
    previousServoTime = currentMillis;
    servoInterval = 60000 / bpm; // Convert BPM to interval in milliseconds

    // Increment or decrement the servo angle
    if (servoAngle == 0) {
      servoAngle = 180;
    } else {
      servoAngle = 0;
    }
  }

  // Output distance and BPM to the serial monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.print(" cm, BPM: ");
  Serial.print(bpm);
  Serial.println(" beats per minute");

  // Generate buzzer tone based on frequency
  int frequency = map(distance, 0, 100, 100, 500);
  tone(buzzerPin, frequency);

}