View source for Lab-in-a-Box

The '''Lab-in-a-Box''' is an introductory electrical engineering project kit and accompanying textbook used for [[gp:ECE 2074 Electric Circuit Analysis Laboratory|ECE 2074 Electric Circuit Analysis Laboratory]] and [[gp:ECE 3074 AC Circuit Analysis Laboratory|ECE 3074 AC Circuit Analysis Laboratory]]. It includes a [[w:Breadboard|breadboard]] called the A&D or "ANDY" board.

=ANDY Board=
The ANDY board has ±9V and +5V sources, clock signal, sine/square wave signal generator, 16 dipswitches, 16 LEDs, and two pushbutton switches. The dipswitches and LEDs are used for digital applications in [[gp:ECE 2504 Introduction to Computer Engineering|ECE 2504 Introduction to Computer Engineering]]. The signal generator is for RC circuits in the [[gp:ECE 2074 Electric Circuit Analysis Laboratory|ECE 2074]].

[http://www.ece.vt.edu/cel/Kits/A&D-User-Manual&Test-Procedure-v2.2.pdf A&D User Manual & Test Procedure v2.2]

=Parts Kit=
The parts included with the kit include resistors, capacitors, inductors, light emitting diodes, and a handful of integrated circuits including operational amplifiers, and digital logic chips.

[http://www.ece.vt.edu/cel/Kits/ECE2074&ECE3074-Parts-Kit.html Part Kit Description for ECE 2074 & 3074]

=Carrying/Storage Box=
Some of the articles on the Lab-in-a-Box mention a "high-end tackle box from Walmart" that is used to hold the ANDY board an all of the parts.   (Make & Model?)

=Software Oscilloscope=
==Attenuator Circuit==
The attenuator circuit in the Lab-in-a-Box manual is setup for the gain of the Behringer UCA202 on Windows XP. You can either work with your teaching assistant to develop an attenuator circuit that fully compensates for the gain of your system in hardware or use the software tweaks to [[xoscope]] described below.

The [http://www.ece.vt.edu/tutorials/labinabox.php  ECE: Lab-in-a-Box Tutorials] page has an article [http://www.ece.vt.edu/tutorials/download/Expt12_v5.1.pdf Experiment 12: Calibrating A Sound Card Oscilloscope].  A schematic to be built on the ANDY board is on page 3.  The tutorial uses the Zeitnitz windows oscilloscope software.

==Software==
While [[xoscope]] or the Lab-in-a-Box attenuator circuit could use some tweaking to work out of the box together, xoscope can be readily modified to display scaled maximum, minimum and peak-to-peak values. The first step is to obtain the program source code. On a Debian-based systems like Ubuntu, just run <code>sudo apt-get source xoscope</code>.

Once the source has been downloaded and unpacked, edit <code>sc_linux.c</code> to use <code>/dev/dsp1</code> rather than <code>/dev/dsp</code>:
<pre>
sed -ir 's%(#define SOUNDDEVICE "/dev/dsp)(")%\11\2%'
</pre>

Next, modify the display code in <code>display.c</code> to display a scaled value. Around line 186, change the code to read something like the snippet below. Use your multimeter to measure the the RMS voltage, calculate the peak-to-peak that should be displayed and tweak the divisor, re-compile and re-run until the value is correct.
<pre>
    else
        sprintf(string, " Max:%f - Min:%f = %f Pk-Pk ",
                (float)stats.max / 3.2, (float)stats.min / 3.2,
                ((float)stats.max - (float)stats.min) / 3.2 );
    gtk_label_set_text(GTK_LABEL(LU("min_max_label")), string);
</pre>

To compile the modified source, simply run <code>make</code>. To run the newly compiled binary, run <code>./xoscope</code>. Refer to the [[xoscope|xoscope article]] for instructions on using the scope.

=External Links=
* [http://www.vtnews.vt.edu/story.php?relyear=2009&itemno=20 VT news story]
* [[CEL]] listing of the [http://www.ece.vt.edu/cel/Kits/ECE-Lab-Kits.html#ECE2074ECE3074 lab kit]

[[Category:Hardware]]
[[Category:Deprecated]]