IF Statement continues execute even when false

Using Arduino Programming Questions
1

Hello,

I've tried to find what I could on the forums regarding this without spending my whole night, so I apologize if this is repetitive.

I am trying to build a musical keyboard that produces tones from push buttons. When no buttons are pressed, I would like no sound. I am only using two buttons at the moment for testing my code.

I am using the code below for testing:

void setup()
{
Serial.begin(9600);
pinMode(52, INPUT);
pinMode(53, INPUT);
}
 
void loop()
{ 
  Serial.print(digitalRead(53));
  Serial.print(digitalRead(52));
  Serial.println(" ");


if (digitalRead(53) == HIGH){
  tone(12, 261); 
  }

if (digitalRead(52) == HIGH){
   tone(12, 392); 
  }

 }

The operation goes as follows:
-Initially, when the buttons are unpressed, no sound is produced. Perfect --
-When I press either of the two buttons, the tone corresponding to that buttonstates IF statement is executed - again perfect.
-However, when I let go, the tone continues to play until I either press the on board RESET button, or until I press the other push button. And when I press the other push button the same problem occurs.

What I've already tried:

  • A different button.
  • I've verified the button state with Serial.print - all good.
  • I've tried adding short delays after the button state is read in (by assigning the digitalRead(x) to a variable, delaying, and then checking the state of the variable).
  • Else statements were successful at stopping the tone when the button was released, but created a bias to one button over the other when played simultaneously, or "rolling the keys" where the next button is pressed before the other is released.

Any suggestions? Thanks in advance.

2

How do you have the buttons wired? I presume the buttons are connected to 5v. Do you have pulldown resistors on those pins also?

And you also need to call noTone() to stop the tone.

if (digitalRead(53) == HIGH){
  tone(12, 261);
}
else if (digitalRead(52) == HIGH){
   tone(12, 392);
}
else noTone(12);

edit: My bad. I forgot the pin on noTone.

3

So where in your code do you ever do anything to turn the tone off? You turn it on when you see a button press, but nowhere do you turn it off when the button is no longer pressed. The IF is doing exactly what your code says to do....

Regards,
Ray L.

4

It might not be a problem with your buttons. You need to check what that tone( ) function is doing.

5

@ SurferTim:
The buttons are wired with 5V and pull down resistors at a value of 10 K ohm. I'll try the code you posted in a bit - but I seem to remember the else if's and else statements producing that bias I mentioned when "rolling the keys"

@ RayLivingston:
Introducing the noTone() function causes a very bad distortion, making the tone unrecognizable. I've tried it inside an IF block, in a separate IF block (if digialRead(52) == LOW), and also at the very end of the loop. In each case the distortion occurs.

@michinyon:
Beyond changing the parameters of tone() and observing what happens, what else could I do to check what that function is doing?

Thanks guys --

6

So, you changed your code, and you want us to guess what changes you made. I'll pass.

7