Concept

For this week’s assignment, Daniel and I constructed a musical instrument that measures the distance between the ultrasonic sensor and anything placed in front of it (i.e., your hand). Depending on how far you place your hand/ an object from the sensor, the piezo buzzer will play one of 8 different notes we inputted into the code.

To do this, we used a force-sensing resistor that you had to press on whenever you wanted the ultrasonic sensor to detect your hand and a piezo buzzer that would play the sound as output.

Inspiration:

https://www.youtube.com/watch?v=J8XNTHETgxU&list=PL9sNGWKp-dXUYcIGeJQFZ2mal6_zI-p5h&index=1&t=123s

Schematic

Code

int trig = 10; // digital 10
int echo = 11; // digital 11
long duration;
long distance;
int force;
 
 
void setup() {
 // runs once
 pinMode(echo, INPUT); // digital 11 
 pinMode(trig, OUTPUT); // digital 10
 Serial.begin(9600); // open serial monitor to track
}
 
void loop() {
 // runs repeatedly
 digitalWrite(trig, LOW);
 delayMicroseconds(2);
 digitalWrite(trig, HIGH);
 delayMicroseconds(10);
 digitalWrite(trig, LOW);
 duration = pulseIn(echo, HIGH);
 distance = (duration / 2 * 0.0344);
 
 int notes[7] = {233, 261, 293, 311, 349, 392, 440};
 //              Bb    C   D     Eb    F   G   A    
 
 force = analogRead(A0); // analog 0
 
 if (distance < 0 || distance > 50 || force < 100){
   noTone(12);
 
 } else if (force > 100){
   int sound = map (distance, 0, 50, 0, 7);
   tone(12, notes[sound]);
  
 }
}

The seven notes we inputted are:

• Do (233)
• Re (261)
• Mi (293)
• Fa (311)
• So (349)
• La (392)
• Ti (440)

Video

Daniel is shown playing Twinkle, Twinkle, Little Star using the instrument.

Link to video

Reflection and Improvements

• The ultrasonic sensor was very sensitive to movement very close to it, but the farthest note (Ti), was very hard to detect just because it was so far away from the sensor. This made the sound laggy when it came out of the piezo buzzer, which made the song sound very untuned and the note inconsistent.