Tone generation library

For those who are interested, I've created a tone generation library for the Arduino. It is non-blocking (it will play tones while the rest of your program is working) and produces square wave tones only.

http://code.google.com/p/arduino-tone/

Tones can be played on any pin, but you are limited to the number of tones (depending on the type of Arduino you have).

Just connect the digital pin to a speaker with an in-line series resistor - say 1K, and the other side of the speaker to ground (GND).

You could also use a potentiometer to control the volume - I'd suggest a 10K pot.

Included in the library are three examples:

1. simple dual tone player (notes selected through serial port)
2. DTMF (Dual Tone Multiple Frequency) example.
3. RTTTL (Ring Tone Text Transfer Language) example.

Try it out! Tell me what you think.

b

Tom Igoe wrote this easy to use Theremin example. See how you can translate the values from the analog pin to frequencies directly using the map() function?

/*
   Theremin

  Plays notes based on a sensor reading
  uses Tone library by Brett Hagman
  http://code.google.com/p/arduino-tone/

  circuit:
  * potentiometer on analog in 0
  * 8-ohm speaker on digital pin 8

  created 18 Aug 2009
  by Tom Igoe

  */

#include <Tone.h>


Tone musicMaker;              // instance of the tone library
int lastSensorReading = 0;    // value of the previous sensor reading
int threshold = 10;           // minimum difference between readings


void setup() {
   Serial.begin(9600);
   // start the music:
   musicMaker.begin(11);
}

void loop() {
   // read an analog input:
   int sensorReading = analogRead(0);
   // map the analog readings to a range from A3 to G5:
   int thisTone = map(sensorReading, 0, 1023, NOTE_A3, NOTE_G5);
   // if the sensor reading is different enough
   // from the last sensor reading, change the pitch:
   if (abs(sensorReading - lastSensorReading) > threshold) {
     musicMaker.play(thisTone);
     // save the current sensor reading
     // for next time through the loop:
     lastSensorReading = sensorReading;
   }
}

These examples look great. Can't wait to try them out.

Many thanks for sharing your code.

Wow! Great job with this library. The RTTL reader is way cool and a lot of fun. I've only heard it with a piezo so far, but it literally rocks!

Thanks for contributing this. It's really a sound improvement for the Arduino.

I was looking for just this kind of code library just yesterday. Absolutely brilliant! It works with a piezo transducer I picked up at Radio Shack too. Thanks!

Works well here too. Kudos.

There is also a snippet in the daniweb library for windows machines, you can find it

Regards...

Rocky

Cool stuff!
Thanks for sharing the code.

nice one thanxxx

Very cool! I will try it.
Thanks!
Julián

awesome work keep it up..........

Does the Tone Library work with an ATmega328P running at 1MHz from the internal oscillator? The tones seem way too low but I could easily be doing something wrong.

Is anyone else interested in the Tone Library working at 1MHz?

Why not modify the play method in that library to multiply the given frequency by 16. You could use the F_CPU define or clockCyclesPerMicrosecond() to check the actual clock frequency assuming you are setting this in your boards.txt file

adding something like this at the top of the play method should work (although I have not tried it):
frequency = frequency * (16 / clockCyclesPerMicrosecond());

Thank you for the reply.

Why not modify the play method in that library to multiply the given frequency by 16

Good thinking! That will at least tell me if I'm doing somthing wrong or if there's a deficiency in the library.

You could use the F_CPU define

The library uses F_CPU to calculate the configuration values for the counter. Unfortunately, I suspect the various frequency / divisor ranges are designed to only work for 16MHz and 8MHz clocks.

assuming you are setting this in your boards.txt file

I am. And from some blink / delay testing I think I did it correctly.

adding something like this at the top of the play method should work (although I have not tried it):
frequency = frequency * (16 / clockCyclesPerMicrosecond());

I think it will work for 16MHz and 1MHz but it will probably not work for 8MHz. But, I'll certainly try it.

The prescalar selection for the timers were based on 16 MHz (and they we're OK for 8 MHz, but not great).

I changed the code to scan for the best prescalar based on the frequency and cpu clock.

I've uploaded a new version - I haven't tested it out on hardware just yet, but it does compile. Please test it and let me know if it works for you.

http://code.google.com/p/arduino-tone/source/browse/trunk/Tone.cpp

b

It works well for higher frequencies but a tone that should be 100Hz is 555Hz on one of the pins.

I tested using this sketch on an a standard 16mhz ATmega168 :

#include <Tone.h>

int notes[] = { 20,50, 100, 1000, 5000, 10000, 15000, 20000};
Tone notePlayer[2];

void setup(void)
{
  Serial.begin(9600);
  notePlayer[0].begin(11);
  notePlayer[1].begin(12);
}

void loop(void)
{
  char c;

  if(Serial.available())
  {
    c = Serial.read();
    
    switch(c)
    {
      case 'a' ... 'h':

        notePlayer[0].play(notes[c - 'a']);
        Serial.print("pin 11:");
        Serial.println(notes[c - 'a']);
        break;
      case 's':
        notePlayer[0].stop();
        break;

      case 'A'...'H':   
        notePlayer[1].play(notes[c - 'A']);
        Serial.print("pin 12:");
        Serial.println(notes[c - 'A']);
        break;
      case 'S':
        notePlayer[1].stop();
        break;

      default:
        notePlayer[1].stop();
        break;
    }
  }
}

Setting both outputs to 100Hz, I measured a period of just over 1.8ms on pin12. The period onr pin 11 was spot on (9.982ms).

The original code was never intended to produce frequencies below 123 Hz, because @16MHz, the 16 bit timers (set at ck/1) could not kill enough time to produce tones lower than that.

Thus, I've rewritten the code to accommodate almost all frequencies now on the 16 bit timers (2 -> 65535 Hz). 8 Bit timers will still choke, but now at 31 Hz.

http://code.google.com/p/arduino-tone/source/browse/#svn/trunk

(note: you'll have to get Tone.h as well now, because of the declaration change).

Coding Badly: Test it at 1MHz - let me know how it goes.

b

Thanks bhagman and mem! I should have time tonight for some testing.

[edit]The results seem to be the same. At 8MHz NOTE_B2 is lower than at 16MHz. At 1MHz NOTE_B2 is even lower. I suspect I need to sleep on it... Good night to all! (or morning or afternoon to those not in America)[/edit]

Hi, i try, this and it seems that i can only have 2 tone?
the third one does not run?
i have a atmega 328 and it should give me 3 tone (at least this is what i anderstand in the .cpp and .h
am i wrong?
Thanks
Patgadget

#include <Tone.h>
Tone tone1;
Tone tone2;
Tone tone3;
void setup()
{
  tone1.begin(13);
  tone2.begin(12);
  tone3.begin(6);
  tone3.play(100);
  tone1.play(35);
  tone2.play(35);
}
void loop()
{
}

Patgadget: Silly boundary conditions. Amazing what a difference >= makes compared to >. Fixed. Get the latest version from Google Code SVN. Thanks for finding it.

Coding Badly: hmmm... methinks you have something else going on. Are you compiling the sketches against F_CPU set to 1MHz? Or are you just compiling based on an Duemilanove w/ATmega32 (@16 MHz) and putting it into a chip running at 1MHz? I'm betting dollars to donuts that you're doing the latter.

b