#!/usr/bin/env perl

use Device::SerialPort::Arduino;

use strict;
use warnings;

my $Arduino = Device::SerialPort::Arduino->new(
  port     => '/dev/tty.usbmodemFA131',
  baudrate => 9600,
  databits => 8,
  parity   => 'none',
);

my $speed = $ARGV[0];

sleep(2);

# Send something via Serial
$Arduino->communicate("$speed")
or die 'Warning, empty string: ', "$!\n";

# receive sth from Arduino with delay
print $Arduino->receive(2), "\n";