gistfile1.txt

#!/usr/bin/perl

# gist url:
# gist-paste -u https://gist.github.com/jaggzh/218c2640f87a414854d262a5e127ed95
use strict;
use warnings;
use Device::SerialPort;
use Getopt::Std;
use Time::HiRes qw(time sleep);

# Parse command-line options
my %opts;
getopts("t:b:", \%opts);
my $timeout = $opts{t} // 1.5;
my $baudrate = $opts{b} // 115200;

# Check if the serial port is provided
if (@ARGV < 1) {
    die "Usage: echo something | send-to-serial [-t timeout_in_seconds] [-b baudrate] /dev/ttyUSB0\n";
}

my $port = $ARGV[0];

# Configure the serial port
my $serial = Device::SerialPort->new($port) || die "Could not open serial port: $!";
$serial->baudrate($baudrate);
$serial->databits(8);
$serial->parity("none");
$serial->stopbits(1);
$serial->write_settings;

# Function to read until there's a delay in the output
sub read_until_delay {
    my ($serial, $max_wait, $delay_threshold) = @_;
    my $response = "";
    my $end_time = time + $max_wait;
    my $last_read_time = time;

    while (time < $end_time) {
        my ($count, $data) = $serial->read(255);
        my $current_time = time;
        if ($count > 0) {
            print STDERR "Read $count bytes at $current_time\n";  # Debugging info
            $response .= $data;
            $last_read_time = $current_time;
        } elsif ($current_time - $last_read_time > $delay_threshold) {
            print STDERR "Exiting loop due to delay threshold at $current_time\n";  # Debugging info
            last;
        }
        sleep 0.01;
    }
    
    return $response;
}

# Send a blank line to trigger initialization
$serial->write("\n");

# Read the initialization message
print read_until_delay($serial, 5, 2.5);

# Read from stdin
my $input = do { local $/; <STDIN> };

# Send the actual command
$serial->write($input);

# Read the response
print read_until_delay($serial, $timeout, 2.5);

# Close the serial port
undef $serial;