========
On Jul 2, 7:46 am, zentara <zent...@highstream.net> wrote:
> On Sun, 01 Jul 2007 16:20:57 -0700, pnbe...@gmail.com wrote:
> >I don't know what I am doing but I do know what I want.
> >I am trying write a small Perl/Tk program that takes the data present
> >on /dev/ttyS0 and displays it in a Label widget.
>
> >All that happens is I get a Perl/Tk window that displays "Weigh-
> >Tronix /dev/ttyS0" rather than the actual scale weight. What am I
> >missing here?
> >Thanks for any help.
> >Paul
>
> As felix said, you are just displaying the name of the serialport.
>
> You need to open the serial port and read it like a filehandle.
> As you read the filehandle, you can update the label, but unless the
> messages are extremely short, you may be better off displaying it in a
> Text widget.
>
> Here is a super-simple way of reading the serial port. I'm using the
> Object Oriented Device::Serial port, but you can also try to read the
> port with filehandle directly (but it can be a hassle).
>
> use warnings;
> use strict;
> use Tk;
> use Device::SerialPort;
>
> #my $serial_port = "/dev/ttyS0";
> my $serial_port = new Device::SerialPort ("/dev/ttyS0") || die "can't
> open COM1\n";
>
> #Setup Perl/Tk
> my $mw = MainWindow->new();
> $mw->title("Scale");
>
> #Close button
> my $button = $mw->Button(
>         -text => 'Close',
>         -command => sub {$mw->destroy}  # exit is better here
>         )->pack(
>                 -pady => 20,
>                 -side => 'bottom'
>         );
>
> my $title_label = $mw->Label(
>         -text => "Weigh-Tronix"
>         )->pack(
>                 -side => 'left');
>
> my $input = '---------------';
> my $display_label = $mw->Label(
>         -textvariable => \$input,
>         -width=>15,  #keep the width stable at 15
>                    )->pack(
>          -side => 'left');
>
> # every 100 millisecs update from port
> $mw->repeat(100, sub{
>       $input = $port->input;
>      if(defined $port->input){ $input = $port->input  }
>
> });
>
> MainLoop;
>
> __END__
>
> zentara
>
> --
> I'm not really a human, but I play one on earth.http://zentara.net/japh.html

Thank you very much for the leads.

I read up on filehandles in the Camel book and came up with the
following code that does work:

use warnings;
use strict;
use Tk;

my $serial_port = "/dev/ttyS0";
open(SERIAL, "<$serial_port");
my $scale_weight = <SERIAL>;


#Setup Perl/Tk
my $mw = MainWindow->new();
$mw->title("Scale");

#Close button
my $button = $mw->Button(
	-text => 'Close',
	-command => sub {$mw->destroy}
	)->pack(
		-side => 'bottom'
		);
my $title_label = $mw->Label(
	-text => "Weigh-Tronix"
	)->pack(
		-side => 'left',
		-pady => 5,
		-padx => 5
		);
my $display_label = $mw->Label(
	-textvariable => \$scale_weight
	)->pack(
		-side => 'left',
		-pady => 5,
		-padx => 5
		);

MainLoop;




I will investigate the Device::SerialPort package and thank you very
much for the example on getting the program to refresh the display, I
was wondering how to do that!

Paul