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Topic: Tone generation library (Read 13755 times) previous topic - next topic


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.


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.



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?

Code: [Select]

 Plays notes based on a sensor reading
 uses Tone library by Brett Hagman

 * 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() {
  // start the music:

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) {
    // 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.


Sep 01, 2009, 06:59 pm Last Edit: Sep 01, 2009, 10:33 pm by BroHogan Reason: 1
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.
"Data is not information, information is not knowledge, knowledge is not understanding, understanding is not wisdom."
~ Clifford Stoll


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!  :D


Works well here too. Kudos.


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




Cool stuff!
Thanks for sharing the code.



Very cool! I will try it.


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

Coding Badly

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?


Nov 23, 2009, 08:54 am Last Edit: Nov 23, 2009, 09:07 am by mem Reason: 1
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):
[font=Courier New]  frequency = frequency * (16 / clockCyclesPerMicrosecond()); [/font]

Coding Badly

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.



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