SC_Timer User Guide V2.0r1

Next: , Previous: (dir), Up: (dir)

SC_Timer User Guide

This is the SC_Timer User Guide. It describes how to install and use SC_Timer.

Last edited: 26 March 2012

SC_Timer is Copyright © 2004-2012 Adalog. SC_Timer is free software; you can redistribute it and/or modify it under terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This unit is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License distributed with this program; see file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

As a special exception, if other files instantiate generics from the units of this program, or if you link units provided with this program with other files to produce an executable, these units do not by themselves cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU Public License.

This document is Copyright © 2004-2012 Adalog. This document may be copied, in whole or in part, in any form or by any means, as is or with alterations, provided that (1) alterations are clearly marked as alterations and (2) this copyright notice is included unmodified in any copy.

Please send remarks, good ideas, suggestions for improvement, etc. to

Next: , Previous: Top, Up: Top

1 Introduction

SC_Timer is a timer program which is especially convenient for session chairs in conferences who need to manage their speakers; but the program is really a general count-down (or count-up) timer, and you can use it for all your time counting needs!

In a typical session, the speaker is allocated a certain time, generally 2 minutes for the presentation, and 5 minutes for questions. Ten minutes before the end of the talk, the chair will draw attention of the speaker to the remaining time (we call this the notice time). Five minutes before the end, the chair will start waiving at the speaker that he/she should come to the conclusion (we call this the warning time). And when the time is over, the chair will have to stop the speaker. Extra time taken by the speaker should be subtracted from the time for questions (at least if you don't want the whole schedule to shift).

Sometimes, you may want to simply “stop the clock”, for example if the speaker is interrupted by some non-relevant question, and you don't want to count the interrupt into his time. We call this a pause.

You may also want to cheat, i.e. allocate more (or less time) to the speaker, depending on how interesting the presentation is.

SC_Timer will help you to manage all this.

Next: , Previous: Introduction, Up: Top

2 Installation

2.1 Compiled Windows distribution

The compiled Windows distribution is just a regular setup file; just execute it, and it will install.

Note that SC_Timer does not use the Registry, it does not install files except in its own installation directory, nor do other evil things. You can uninstall the program with the supplied uninstaller, but deleting the installation directory will work as well.

2.2 Compiled Linux distribution

Just put the executable where you please. Make sure Gtk-2 is installed on you system. There is no installation, no parameters, and no environment variables to set. You can uninstall the program simply by deleting the executable file.

2.3 Source distribution

Unzip the distribution where you please. You'll need an Ada compiler, with Gtk and the GtkAda (at least version 2.2.0) binding to build SC_Timer. Your gcc version may or may not be configured to compile Ada. If not, you can get an Ada aware gcc (called Gnat). That's the one we used to make the compiled versions. Gnat can be downloaded from many places, including SourceForge. For more information on how to get Gnat, please visit Gtkada is available from

Once you've installed Gnat and GtkAda, all you have to do is go to the <install-dir>/src directory and do:


Alternatively, if you are under Windows and don't have the “make” utility, do:


If you want to change the user interface, you can use Glade, the Gtk UI builder. The file in directory <install-dir>/glade is the Glade project file that was used to generate the current user interface.

Next: , Previous: Installation, Up: Top

3 Running SC_Timer


        sc_timer -h
        sc_timer [-isS] [-p <mins>] [-n <mins>] [-w <mins>] [-q <mins>]

If SC_Timer is invoked with the “-h” parameter (help), it just prints its usage message and stops, other parameters are not considered.

Otherwise, the parameters are (where <mins> is a integer number):

Set the “iconify on start” option
Display the speaker's panel (normal mode)
Display the speaker's panel (full screen mode)
-p <mins>
Sets the number of minutes for the presentation time (default: 25).
-q <mins>
Sets the number of minutes for the questions time (default: 5).
-n <mins>
Sets the number of minutes for the notice time (default: 10).
-w <mins>
Sets the number of minutes for the warning time (default: 5).

If you just want to have an idea of how SC_Timer works, we recommend that you start the program as:

         sc_timer -p 3 -q 1  -n 2  -w 1

i.e. presentation time = 3 mn., questions time = 1 mn., notice time = 2mn., warning time = 1mn. This way, you won't have to wait 25 minutes to see the effect!

Next: , Previous: Usage, Up: Top

4 Principle of operation

SC_Timer manages two windows: a control panel for the session chair, and a display for the speaker. The speaker's display does not appear initially, unless you started SC_Timer with the “-s” or “-S” option.

The control panel always displays a smaller picture of the speaker's display, for you to control what the speaker sees.

The speaker's display features a big white counter that displays the remaing time. The counter will turn yellow <notice-time> minutes before time is over, then turn red <warning-time> minutes before the end. When the presentation time is over, it will display a big red flashing "Off". Alternatively, the counter can be set to display the elapsed time since the session started, or the talk time, i.e. with deduction of the “paused” time.

There is also a regular clock in the upper right corner that tells you the current time.

Next: , Previous: Principle of operation, Up: Top

5 How to chair a session with SC_Timer

5.1 Preparing the session

At the beginning of your session, start SC_Timer, and select the “durations” tab. Set the various durations according to allocated time and your own preferences.

You can change these values at any time, but they take effect only when you start the session. In other words, if the next speaker has been allocated a different time, you can prepare the parameters while the previous speaker is talking, it will not disrupt the currently running counter.

The “display” tab allows you also to select what is displayed by the timer. By default, it displays the remaining time, but you can change it to the elapsed time (time since started), or to the talk time (time since started less time paused). You can change mode at any time (even when the timer is running), but we do not recommend you do that when chairing a session, because your speaker would get seriously confused! On the other hand, if you use the timer for other timing needs, it may be useful to toggle between remaining and elapsed times.

You can also choose to display the speaker's panel (in a regular window or full-screen) and whether to minimize the control-panel on start, depending to the way you want to use the program, as described below.

5.2 Using two screens

The most comfortable way of chairing a session is to have two screens, one for you and one for your speaker. At the beginning of you session, display the speaker's panel by selecting the “Speaker's panel” check-box. Move the panel to the second screen, tick the “full screen” option, and turn the screen toward the speaker.

Note that the “Display” frame on the control panel always displays exactly the same thing as the speaker's panel, so you can check what the speaker sees.

5.3 Using one screen with speaker's panel

If you have only one screen, you can display the speaker's panel, maximize it, and select “Iconify on start” from the parameters tab of the control panel.

When you press the “Start” button, the control panel is automatically iconified, and you can turn your screen to the speaker for him/her to see. Note that keyboard shortcuts allow you to perform the most important functions without looking at the screen. The control panel will automatically reappear when you reset the counter.

5.4 Using one screen without speaker's panel

You may also want to use SC_Timer to manage your session without the speaker's panel. The small display panel is still convenient for you to look after the remaining time.

5.5 Screen savers

Most of the time, you won't type anything during the session; this means that it is a good idea to disable the screen saver, otherwise it will activate and the displays will disappear...

On windows: there is a small command file named saver.bat proviede in SC_Timer's installation directory. Make sure to copy it to a directory on your path, then

     saver off

will disable the screen saver, and

     saver on

will reenable it. Of course, you can include these commands in a command file that launches SC_Timer.

On Linux: there is a similar command, named gnome-screensaver-command. Run:

     gnome-screensaver-command --inhibit

to disable the screen saver. Note that the screen saver is inhibited while the command is running (it does not return): you should therefore run this in a command line window, start SC_Timer, then kill the command when you are finished with SC_Timer.

5.6 Running the session

When the speaker starts to talk, press the “Start” button (shortcut: “S” key). When the timer turns yellow or red, you may try to attract the attention of the speaker to the screen.

When the counter is started, the “Control” tab shows various useful information: the time of session start, the time questions start, and time of end of the current session, time remaining for the presentation and for the questions, etc.

Note that there is an “Additional time” entry (above the buttons) that you can set (by typing in it or with spin buttons). This allows you to give (or withdraw) the indicated number of minutes to the talk. You can do that at any time.

During the talk, you can suspend the counter by pressing the “Pause” button (shortcut: “P” key). Note that the “Control” tab of the control panel displays the total duration of all pauses, and that the duration of this pause appears on the “Pause” button itself. Press the button again to restart the counter.

Everything you type in the “Message” window at the bottom of the control panel appears on the speaker's display, provided the “Display” check-box is selected. If your speaker insists in not seeing your message, play with the “Display” check-box to make the message flash... The message is cleared by pressing the “Clear” button. Pressing the “Enter” key in the message window forces the display too.

When the time is over (“Off” flashing), make big waves.

When you start the questions part of the session, press the “Start questions” button (shortcut: “Q” key). The timer will restart with the questions time, and go to Off again when the time for questions is over.

You can force the end of the presentation (or the questions) at any time by clicking the “Stop” button.

The “Reset” button (shortcut: “R” key) resets the timer for the next speaker.

5.7 Summary of keyboard shortcuts

When the speaker's display is active, several commands are also available through keyboard shortcuts. This is especially convenient to make the most usual actions while the control panel is hidden.

Shortcut Action
S “Start” button
T “Stop” button.
Q “Start questions” button.
R “Reset” button
1 to 9 add corresponding number of minutes to additional time.
-1 to -9 remove corresponding number of minutes from additional time.

Next: , Previous: How to chair a session with SC_Timer, Up: Top

6 Limitations

SC_Timer can manage times up to 9 hours (32400 minutes). When the time to display is above one hour, it displays hours and minutes instead of minutes and seconds.

Previous: Limitations, Up: Top

7 A final note...

SC_Timer is written in Ada. Apart from being useful (!), it is a demo of how easy it is to develop multi-tasking, GUI oriented, applications with Ada and its Gtk interface, Gtkada. For more information about the Ada language and Adalog services, please visit