use warnings;
use strict;
use Audio::DSP;
$| = 1;

my $sample_rate = 8000; #44100 gives best sound, but highest cpu
#8000 works
my $channels = 1;
my $format = AFMT_S16_LE;
my $buffer = 4096;

my $dsp = new Audio::DSP(buffer => $buffer,
channels => $channels,
format => $format,
rate => $sample_rate);
$dsp->init() || die $dsp->errstr();

################################################## ##########
my $freq_adj = .1;
my $vol = .5;
my $toggle = 1;

while(1)
  {
  make_tone($freq_adj, $vol);
  if(($freq_adj > 4) or ($freq_adj < .1)){ $toggle *= -1;}

  $freq_adj += ($toggle * .001); #higher increment numbers are slower
  #0 is pure tone
  }

sub make_tone 
  {
  my $rad = 0;
  my ($freq_adj, $vol) = @_;
  while ( $rad < 6.283 )
    {
    $rad += $freq_adj;
    my $raw = ($vol*32768) * sin($rad); #max times
    my $num = pack( 'V', $raw );
    $dsp->dwrite($num);
    }
  }