Looking for a Special Delay Library

system · August 21, 2012, 9:51pm

In my case, I want an on-board speaker to play music while driving my car.
Problem: In the music, there are small delays which can disrupt the other actions taking place.
Approach: I'm want to make a special Library which can delay certain actions and not others.
How? Any suggestions?

Here's the music library. Feel free to use it.
The Yankey.h :

/*
  Yankey.h - Library for playing Yankey Doodle.
  Created by Yosef A. Miller, August 20, 2012.
  Released into the public domain.
*/
#ifndef Yankey_h
#define Yankey_h

#include "Arduino.h"

class Yankey
{
  public:
    Yankey(int pin);
    void play(int cycles);
    void quiet();
  private:
    int _pin;
    int _cycles;
};

#endif

The YankeyDoodle.cpp with attempted corrections:

#include "Arduino.h"
#include "Yankey.h"

Yankey::Yankey(int pin)
{
  pinMode(pin, OUTPUT);
  _pin = pin;
}

void Yankey::quiet()
{
  noTone(_pin);
}

void Yankey::play(int cycles)
{
  _cycles = cycles;
  int currentCycle = 0;
  #include "pitches.h"
  
  // notes in the melody:
  int lowYankey[] = {
    NOTE_G3,
    NOTE_G3,
    NOTE_A4,
    NOTE_B4,
    NOTE_G3,
    NOTE_B4,
    NOTE_A4,
    NOTE_D3,
    NOTE_G3,
    NOTE_G3,
    NOTE_A4,
    NOTE_B4,
    NOTE_G3,
    NOTE_FS3,
    NOTE_G3,
    NOTE_G3,
    NOTE_A4,
    NOTE_B4,
    NOTE_C4,
    NOTE_B4,
    NOTE_A4,
    NOTE_G3,
    NOTE_FS3,
    NOTE_D3,
    NOTE_E3,
    NOTE_FS3,
    NOTE_G3,
    NOTE_G3 };
    
  int highYankey[] = {
    NOTE_E3,
    NOTE_FS3,
    NOTE_E3,
    NOTE_D3,
    NOTE_E3,
    NOTE_FS3,
    NOTE_G3,
    NOTE_E3,
    NOTE_D3,
    NOTE_E3,
    NOTE_D3,
    NOTE_B2,
    NOTE_B2,
    NOTE_D3,
    NOTE_E3,
    NOTE_D3,
    NOTE_E3,
    NOTE_D3,
    NOTE_E3,
    NOTE_FS3,
    NOTE_G3,
    NOTE_G3,
    NOTE_D3,
    NOTE_G3,
    NOTE_FS3,
    NOTE_A4,
    NOTE_G3,
    NOTE_G3   };
    
    int lowDurations[] = {4,4,4,4,4,4,4,4,4,4,4,4,2,2, 4,4,4,4,4,4,4,4,4,4,4,4,2,2};
    int highDurations[] = {3,8,4,4,4,4,4,4,3,8,4,4,2,2, 4,4,4,4,4,4,4,4,4,4,4,4,2,2};
    
    while (currentCycle < _cycles)
    {
      for (int thisNote = 0; thisNote < 28; thisNote++) {
        
        // to calculate the note duration, take one second 
        // divided by the note type.
        //e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
        int lowDuration = 1000/lowDurations[thisNote];
        tone(_pin, lowYankey[thisNote],lowDuration);
    
        // to distinguish the notes, set a minimum time between them.
        // the note's duration + 30% seems to work well:
        int pauseBetweenNotes = lowDuration * 1.30;
            
            // special delay function
            unsigned long millis();
            int timeOld = millis();
            int x = 1;
            while (x < 2 )
            {
              int timeNew = millis();
              if ((timeNew - timeOld) >= pauseBetweenNotes)
              {
                x = 3;
              }
            }
          }
            
        // special delay function
            unsigned long millis();
            int timeOld = millis();
            int x = 1;
            while (x < 2 )
            {
              int timeNew = millis();
              if ((timeNew - timeOld) >= 150)
              {
                x = 3;
              }
            }
      
      for (int thisNote = 0; thisNote < 28; thisNote++) {
        // to calculate the note duration, take one second 
        // divided by the note type.
        //e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc.
        int highDuration = 1000/highDurations[thisNote];
        tone(_pin, highYankey[thisNote],highDuration);
    
        // to distinguish the notes, set a minimum time between them.
        // the note's duration + 30% seems to work well:
        int pauseBetweenNotes = highDuration * 1.30;
        
        //special delay function
            unsigned long timeNew;
            int timeOld = millis();
            int x = 1;
            while (x < 2 )
            {
              int timeNew = millis();
              if ((timeNew - timeOld) >= pauseBetweenNotes)
              {
                x = 3;
              }
            }
          }
        currentCycle++;
        }
    // stop the tone playing:
    noTone(_pin);
  }

The pitches.h you'll need with it:

/*************************************************
 * Public Constants
 *************************************************/

#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 4978

The code attempted to make it run in backround:

#include <Servo.h>                    // Include servo library
#include <Yankey.h>
 
Servo servoLeft;                      // Declare left and right servos
Servo servoRight;

Yankey yankey(4);                     // Pin number the speaker is attached to
 
void setup()                          // Built-in initialization block
{ 
  yankey.play(2);                     // Play Yankey Doodle twice
  
  servoLeft.attach(11);               // Attach left signal to P13 
  servoRight.attach(12);              // Attach right signal to P12

  // Full speed forward
  servoLeft.writeMicroseconds(1700);  // Left wheel counterclockwise
  servoRight.writeMicroseconds(1300); // Right wheel clockwise slower     

  servoLeft.detach();                 // Stop sending servo signals
  servoRight.detach(); 
}  
 
void loop()                           // Main loop auto-repeats
{
                                      // Nothing needs repeating
}

system · August 21, 2012, 10:04pm

Approach: I'm want to make a special Library which can delay certain actions and not others.

You can't do that. What you can do is to make sure that certain actions are performed at the appropriate time, as in the Blink Without Delay example.

The code attempted to make it run in backround:

On a machine with no operating system, and a single thread, there is NO background for processes to run in.

system · August 22, 2012, 12:02am

Here is my attempt. This I think should've worked. Can you explain why not?:

    //special delay function
    unsigned long millis();
    int timeOld = millis();
    int x = 1;
    while (x < 2 )
    {
      int timeNew = millis();
      if ((timeNew - timeOld) >= pauseBetweenNotes)
      {
        x = 3;
      }
    }

system · August 22, 2012, 12:13am

I now see something wrong. The while loop is basically a delay. It needs to wait until it's out of the while loop until it can continue.

MichaelMeissner · August 22, 2012, 12:17am

I saw a posting about the QP state machine for Arduino posted within the last month. If you went to a state machine like they use, it would allow you to deal with multiple delays, etc. http://arduino.cc/playground/Code/QP.

system · August 22, 2012, 8:37am

You can do that by one or several counters decrements by a timer interrupts.

Here the code to initialize and handle the interrupt :

volatile unsigned long myCounter = 0;

void setup()
{
  TCCR1B = (TCCR1B & ~_BV(WGM13)) | _BV(WGM12);                  // Set CTC mode (Clear Timer on Compare Match)
  TCCR1A = TCCR1A & ~(_BV(WGM11) | _BV(WGM10));                  // ...
  TCCR1B = (TCCR1B & ~(_BV(CS12) | _BV(CS11))) | _BV(CS10);      // No prescaler
  OCR1A = 160;                                                   // Set the compare register (16e6 Hz / 100000 Hz = 160) for 10 uS
  TIMSK1 |= _BV(OCIE1A);                                         // Enable interrupt when TCNT1 == OCR1A 
}

ISR(TIMER1_COMPA_vect)
{
   if (myCounter)
   {
      myCounter--;
   }
}

Then in your loop you can initialize the counter(s) to execute or not execute parts of code :

void loop()
{
    // code always execute
    // ...
    // ...
    
    if (!myCounter)
    {
        // code execute only each 2 milliseconds
        // ...
        // ...
        myCounter = 200 // value for 2 milliseconds
    }
    
    // code always execute
    // ...
    // ...
    
}

JLB

system · August 23, 2012, 1:53pm

I totally don't get the setup code! Could you please explain.

system · August 23, 2012, 3:22pm

The comments in the setup function explain what is happening as clearly as possible without going into great detail.
All it basically does is set up a timer to call a function every 10 uS.
That function decrements the integer 'myCounter' until it reaches 0.

Inside of your loop function, there is a test to see if myCounter has reached 0. When it does, you are to play the next note in your song and reset myCounter to 200.

Since the counter is decremented every 10 uS for a total of 200 times before the conditional block is called, it takes ~2ms for the for the conditional block to evaluate as true. In the meantime, there is more or less no delay for the rest of the code you want to execute.

When it is all said and done, however, I doubt that is even necessary. Especially with a song like yankee doodle where the tone does not have to change any where near as often as 2 ms. You should be fine using the millis() function and good ole subtraction on a cached int without any noticeable limitations.

system · August 24, 2012, 9:59am

I think the best way to implement a background melody player is to set the timer interrupt for the minimal duration being used by a melody.

The interrupt routine can play a table with frequency and duration of each note (don't forget the pause).

Using this method the normal code of your application can execute without any care about the player.

JLB

PS : You have to enable interrupts at the start of your interrupt routine to avoid disfunctionnement on other interrupts routines.

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