speed up wav file using TMRpcm

Projects Programming
1

hello, how would i speed up a wav file? i tried a few ways of doing it but i could not manage to change the sample rate, the script that i have written plays a wav file from a sd card when the receivers value is at the correct value.

Thanks

#include <pcmConfig.h>
#include <pcmRF.h>
#include <TMRpcm.h>
#include <SPI.h>
#include <SD.h>
#define SD_CARD 10
TMRpcm sample;
TMRpcm sample1;

volatile int pwm_value = 0;
volatile int prev_time = 0;
int rev = 0;
int enginestage = 0;
int previousengine = 0;

void setup()
{
  attachInterrupt(0, rising, RISING);
  Serial.begin(9600);
  pinMode(7, INPUT);

  randomSeed(analogRead(0));
  sample.speakerPin = 9;
  if (!SD.begin(SD_CARD))
  {
    return;
  }
  sample.volume(7);
}

void loop()
{

  rev = pwm_value / 13;

  if (rev == 109) {
    enginestage = 1;
  }
  if (enginestage != previousengine) {
    if (enginestage == 1) {
      sample.play("1.wav", 1);
      delay(50);
      previousengine = enginestage;

    }
  }
}
void rising() {
  attachInterrupt(0, falling, FALLING);
  prev_time = micros();
}

void falling() {
  attachInterrupt(0, rising, RISING);
  pwm_value = micros() - prev_time;
  Serial.println(rev);
}
2

you could write your own WAV read function that skips samples e.g. every other ?

3

robtillaart:
you could write your own WAV read function that skips samples e.g. every other ?

could you point me in the wright direction please. thanks

4

This simple WAV demo might give you some ideas.

If you actually want to change the sample rate within the WAV file I suggest using a PC program such as Audacity.

...R

5

Robin2:
This simple WAV demo might give you some ideas.

If you actually want to change the sample rate within the WAV file I suggest using a PC program such as Audacity.

...R

hello, im trying to get the wav file to play faster, my goal is to use my transmitters throttle to in crease the speed of a wav clip, i dont have that much experience with playing wav files. ill check out that link in a seconds. thanks

6

ryisnelly10:
hello, im trying to get the wav file to play faster,

Then you either need to skip some of the samples or decrease the interval between samples.

It should be fairly obvious how to make those changes in my demo program.

Of course either of them will distort the sound. I suspect playing faster while compentating for distorting the sound is beyond the scope of an Arduino.

...R

7

Robin2:
It should be fairly obvious how to make those changes in my demo program.

...R

just finished playing around with your demo and you are right there is alot of distortion, might have to leave this idea behind, do you have a any suggestions on what i could try next?

thanks

8

ryisnelly10:
do you have a any suggestions on what i could try next?

Sorry, not a clue. Audio is not my field - beyond playing my CD player.

Well, one idea occurred to me while making a cup of tea. What about having a few different files which sound different (i.e. faster) even when played at the correct speed. Then select which one to play depending on the speed controller. You could create the files on a PC to get the effects you want.

...R