2

I used toneMelody example code (sketch sample 02.Digital->toneMelody) on an Arduino UNO. Then I wanted to blink an LED with the melody.

Here's the code:

#include "pitches.h"
#define BLUE 3 // pin 3 does not blink. but, pin 9 ok.
#define GREEN 5
#define RED 6

int melody[] = {
  NOTE_C4, NOTE_G3, NOTE_G3, NOTE_A3, NOTE_G3, 0, NOTE_B3, NOTE_C4
};    
int noteDurations[] = {
  4, 8, 8, 4, 4, 4, 4, 4
};

void setup() {
  for (int thisNote = 0; thisNote < 8; thisNote++) {
    analogWrite(RED, 0);
    analogWrite(GREEN, 0);
    analogWrite(BLUE, 0);
    int noteDuration = 1000 / noteDurations[thisNote];
    tone(8, melody[thisNote], noteDuration);    
    int pauseBetweenNotes = noteDuration * 1.30;
    int color = melody[thisNote] % 5;
    if(color == 0) {   
      analogWrite(RED, 200);
    } else if(color == 1) {   
      analogWrite(GREEN, 200);
    } else {
      analogWrite(BLUE, 200);
    }
    delay(pauseBetweenNotes);
    noTone(8);
  }
  analogWrite(RED, 0);
  analogWrite(GREEN, 0);
  analogWrite(BLUE, 0);
}

void loop() {
  // no need to repeat the melody.
}

Unfortunately, pin 3 did not blink. But it worked when I changed pin 3 to pin 9.

To check whether pin 3 or Blue LED is broken, I checked with the following code.

#define BLUE 3

void setup() {
  analogWrite(BLUE, 0);
}

void loop() {
  for(int i = 0 ; i < 255 ; i ++) {
    analogWrite(BLUE, i);
    delay(10);
  }    
  analogWrite(BLUE, 0);
}

This code worked. Blue LED blinked. Why couldn't pin 3 blink with toneMelody?

Thanks.

5

In the tone function reference you can read:

Use of the tone() function will interfere with PWM output on pins 3 and 11 (on boards other than the Mega).

analogWrite() is PWM

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.