Final Project

For my final project, I would like to make a music instruemnt like Theremin organ, which is the only instrument in the world that player doesn't need to touch.

To make this instrument, I find HC-SR04 ultrasonic sensor to measure the distance and a buzzer to make the sound.

I found code of how to use HC-SR04 on the Internet:

const int TrigPin = 2;
const int EchoPin = 3;
float cm;
void setup()
{
Serial.begin(9600);
pinMode(TrigPin, OUTPUT);
pinMode(EchoPin, INPUT);
}
void loop()
{
//发一个10ms的高脉冲去触发TrigPin
digitalWrite(TrigPin, LOW);
delayMicroseconds(2);
digitalWrite(TrigPin, HIGH);
delayMicroseconds(10);
digitalWrite(TrigPin, LOW);

cm = pulseIn(EchoPin, HIGH) / 58.0; //算成厘米
cm = (int(cm * 100.0)) / 100.0; //保留两位小数
Serial.print(cm);
Serial.print("cm");
Serial.println();
delay(1000);
}const int TrigPin = 2;
const int EchoPin = 3;
float cm;
void setup()
{
Serial.begin(9600);
pinMode(TrigPin, OUTPUT);
pinMode(EchoPin, INPUT);
}
void loop()
{
//发一个10ms的高脉冲去触发TrigPin
digitalWrite(TrigPin, LOW);
delayMicroseconds(2);
digitalWrite(TrigPin, HIGH);
delayMicroseconds(10);
digitalWrite(TrigPin, LOW);

cm = pulseIn(EchoPin, HIGH) / 58.0; //算成厘米
cm = (int(cm * 100.0)) / 100.0; //保留两位小数
Serial.print(cm);
Serial.print("cm");
Serial.println();
delay(1000);
}
	 	

This code make HC-SR04 work at first time, but it has some noise to be eliminated.

#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 4978
	 	

I used the frequency of C3,D3,E3,F3,G3,A3,B3,C4, which is alto sound of C major.

Soon I found that the speaker sounds better than buzzer, and I can change the volume of the speaker through changing the value of resistance between the speaker and the ground.

At the same time, I found some fixed sheet on the Internet to make my keyboard play fixed songs. I put them into the keyboard. But soon I found that it's not interesting at all. There's nothing cooler than play your own songs on the keyboard! So I canceled that function to make it just a simple keyboard.

However, it's still interesting to play a fixed rhythm by electric sound, which makes it like a metronome, but the tone can be changed.

After changing and tuning, I finally decide it's function and achieve them. Here's the code:

int length;
int TrigPin = 2;
int EchoPin = 3;
int TonePin=4;
int SensorPin=A0;
int sensorValue;
int buttonPin=A1;
int ledPin=13;
int State = 0;
float cm;
float cm1;
void setup()
{
Serial.begin(9600);
pinMode(TrigPin, OUTPUT);
pinMode(EchoPin, INPUT);
pinMode(TonePin,OUTPUT);
pinMode(buttonPin,INPUT);
pinMode(ledPin,OUTPUT);
}
void loop()
{


//发一个10ms的高脉冲去触发TrigPin
digitalWrite(TrigPin, LOW);
delayMicroseconds(2);
digitalWrite(TrigPin, HIGH);
delayMicroseconds(10);
digitalWrite(TrigPin, LOW);
cm = pulseIn(EchoPin, HIGH) / 58.0; //算成厘米
if(cm<100){
   cm1=cm;
}
cm1 = (int(cm1 * 100.0)) / 100.0; //保留两位小数
cm=cm1;
  if(cm<16)
  {tone(TonePin,262);}
  else if(cm<22){
    tone(TonePin,294);
  }else if(cm<26){
    tone(TonePin,330);
  }  else if(cm<32){
    tone(TonePin,350);
  }  else if(cm<37){
    tone(TonePin,393);
  }  else if(cm<41){
    tone(TonePin,441);
  }  else if(cm<46){
    tone(TonePin,495);
  }else if(cm<50){
    tone(TonePin,523);
  }else{noTone(TonePin);}
digitalWrite(ledPin,HIGH);
sensorValue = analogRead(SensorPin);
Serial.println(sensorValue);
if (sensorValue>50){
  delay(sensorValue);
  noTone(TonePin);
    digitalWrite(ledPin,LOW);

  delay(20);
  }else{
  delay(100);
}
Serial.print(cm);
Serial.print("cm");
Serial.println(); }


	 

I put more information about the apperence of my Fantastic Keyboard on my netdisk:https://pan.baidu.com/s/1pLaEtXT,the password is k3ut.