function "tone"

Using Arduino Programming Questions
1

I'm working in a keyboard project and I wrote this simple code:

void setup(){

}

void loop(){
tone(2, 264);
tone(3, 297);
}

I put a push-button attached to each pin that when pressed make the piezoelectric speaker work.

But the problem is that, only the pin 2 works. Why and how to fix?

2

I put a push-button attached to each pin that when pressed make the piezoelectric speaker work.

How did you connect the pushbuttons ? Was there any extra code involved ?

3

From the tone() reference page:

A duration can be specified, otherwise the wave continues until a call to noTone().
...
Only one tone can be generated at a time. If a tone is already playing on a different pin, the call to tone() will have no effect.

Does it make sense now?

4

Alright, thank you guys.
Now I have a new code:

/*
1dó = 264
2ré = 297
3mi = 330
4fa = 352
5sol = 396
6la = 440
7si = 495
8dó = 528
*/
int speaker = 12;
void setup() {
pinMode(2, INPUT);
pinMode(3, INPUT);
pinMode(4, INPUT);
pinMode(5, INPUT);
pinMode(6, INPUT);
pinMode(7, INPUT);
pinMode(speaker, OUTPUT);
}

void loop() {

int i;
int button;
for (i = 2; i < 8; i++) {

if (digitalRead(i) == HIGH) {
button = i;

switch (button) {
case 2:
tone(speaker, 264);
break;
case 3:
tone(speaker, 297);
break;
case 4:
tone(speaker, 352);
break;
case 5:
tone(speaker, 396);
break;
case 6:
tone(speaker, 440);
break;
case 7:
tone(speaker, 495);
break;
default:
noTone(speaker);
break;
}
}
}
}

But now when i press any button, the speaker don't stop. Even with the noTone.
What's wrong??

5

Code logic, that what's wrong.

When no button is pressed, the digitalRead() will see no HIGH and the noTone() is not called.

6

THANKS A LOT, GUYS! Now the code works! If you have any tips for me, I will appreciate :slight_smile:

int speaker = 12;

void setup() {
pinMode(2, INPUT);
pinMode(3, INPUT);
pinMode(4, INPUT);
pinMode(5, INPUT);
pinMode(6, INPUT);
pinMode(7, INPUT);
pinMode(speaker, OUTPUT);
}

void loop() {

int i;

for (i = 2; i < 8; i++) {

if (digitalRead(i) == HIGH) {

switch (i) {
case 2: do {
tone(speaker, 264);
} while (digitalRead(2) == HIGH);
noTone(speaker);
break;
case 3: do {
tone(speaker, 297);
} while (digitalRead(3) == HIGH);
noTone(speaker);
break;
case 4:
do {
tone(speaker, 352);
} while (digitalRead(4) == HIGH);
noTone(speaker);
break;
case 5: do {
tone(speaker, 396);
} while (digitalRead(5) == HIGH);
noTone(speaker);
break;
case 6: do {
tone(speaker, 440);
} while (digitalRead(6) == HIGH);
noTone(speaker);
break;
case 7: do {
tone(speaker, 495);
} while (digitalRead(7) == HIGH);
noTone(speaker);
break;
}
}
}
}

7

A software engineer looks from a larger distance at the problem. You have buttons and frequencies with code that glues it together.

Let's put the data in arrays:

const int buttonPins[] = { 2, 3, 4, 5, 6, 7 };
const int freqList[] = {264, 297, 352, 396, 440, 495 };   // 330 and 528 are missing ?

Then you can use the array. The array starts at index 0.

for (i = 0; i < 6; i++) {
    if (digitalRead( buttonPins[i] ) == HIGH) {
      switch (i) {
        case 0: do {
            tone(speaker, freqList[i] );
        ...

Then you can get rid of the switch-case statement.

The moment that a button is pressed, a tone is started.
The moment that a button is released, the tone is stopped.
That is the State Change Detection: https://www.arduino.cc/en/Tutorial/StateChangeDetection

To add the State Change Detection to your sketch, you have to reorganize your sketch.

For some fun: the toneAC library.
It uses fixed pins 9 and 10 for the speaker.
It is louder and it has a basic volume control. That makes it possible to create others sounds, even a fading out sound. A piano sound instead of a boring beep !

If you think that is fun, there is also a Mozzi library. That is for advanced Arduino users, and you need an amplifier. The sounds on that website are the sounds that a Arduino Uno can make.

Do you have a resistor with the speaker ?

You have now a working sketch. I suggest to keep that sketch. When you want to change things, you can create a new sketch, for example with version2 in its name.

8

I didn't know all those things. Certainly I will take a look, thanks!

No, I haven't a resistor with the speaker. Isn't a problem, right?

9

A normal speaker and a piezo speaker require a series resistor of about 150 Ω. That makes the sound less loud, but that's the way it is.