How can i make a note to fade away ???

// Duelling Tones - Simultaneous tone generation.
// To mix the output of the signals to output to a small speaker (i.e. 8 Ohms or higher),
// simply use 1K Ohm resistors from each output pin and tie them together at the speaker.
// Don't forget to connect the other side of the speaker to ground!

// This example plays notes 'a' through 'g' sent over the Serial Monitor.
// 's' stops the current playing tone.  Use uppercase letters for the second.

#include <Tone.h>

int notes[] = { NOTE_A3,
                NOTE_B3,
                NOTE_C4,
                NOTE_D4,
                NOTE_E4,
                NOTE_F4,
                NOTE_G4 };
int lightPin1 =
 5;  //define a pin for Photo resistor
int lightPin2 = 3;  //define a pin for Photo resistor
int lightPin3 = 1;  //define a pin for Photo resistor
int reading;
// You can declare the tones as an array
Tone speaker;

void setup(void)
{
  Serial.begin(9600);
  speaker.begin(8);
}

void loop(void)
{
  reading = analogRead(lightPin1);
  if(reading < 50) speaker.play(220,500);
  else speaker.stop();  

  reading = analogRead(lightPin2);
  if(reading < 50) speaker.play(240,500);
  else speaker.stop();

  reading = analogRead(lightPin3);
  if(reading < 50) speaker.play(280,500);
  else speaker.stop();
}

Hello !!
I'm making a little laser harp and i've just tried the source code above with 3 lasers ,3 photoresistors and one speaker and works great !
I just have one question....
How can i make the notes
fade away
(i hope that's the correct word).For example if i interrupt one of the
laser beams i want a note to be played and when i remove my hand from the laser beam i want the note to stop slowly and not directly(something like the acoustic guitar).As you understand i want the laser beams to work like the strings of a guitar.Is that possible to make it ? I 'm using the tone library that i found in the arduino playground.Is there any library that has notes tha sound like the notes of a guitar ?

Thanks in advance !!!

Tough question, the thing that came in my mind is to use a PWM output and slowly drop the duty cycle to zero. The PWM signal could be flattened by a capacitor and then it steers a transistor from full open to full block. That transistor is somewhere between the Arduino and the speaker.

Never done, just thinking out loud :slight_smile:

This is one video with my work so far.I hope i can find an easy solution to produce midi sounds via arduino.