How to Use Empirisoft's Digital Analogue Slider

This quick tutorial will discuss the specifications of our Digital Analogue Slider (c). Included in the files below are a sample MediaLab script, which has been tested in our shop for correct operation.

[B]Warning[/B]

1. Currently DirectRT does not support reception of long data strings. Though we're working on an update, it's not ready for publication yet. So these instructions are for MediaLab only.

This system was designed to allow researchers to record the position of an analog slider at pre-defined instances in time. This data is transmitted to the computer through the standard serial port. USB-Serial converters may be used if you don't have a hardware serial port.

[B]System Specifications[/B]

1. Power Supply is 9-12 volts DC, center positive, 200 mA or greater.

2. Serial Data Specifications: 19,200 baud, 8 data bits, 1 stop bit, no parity, no handshaking. Data is transmitted to the computer on pin 2 of the serial cable. Data is received from the computer on pin 3 of the serial cable. Pin 5 is ground. No other pins are used.

3. Position Snapshot interval is adjustable between .1 seconds and 999 seconds.

[B]Operation[/B]

When power is first applied to the system, the string "* * * Empirisoft * * *" is transmitted to the host computer. Successful reception of this string means that the communication link is stable and the system is operating properly. You can verify the reception of this string by using a terminal program (for example, RealTerm or HyperTerm) if you'd like.

The system responds to commands contained within curly brackets: {}.

[B]Start Capture[/B]

To activate the system, send the command {X}

where X is the number, in tenths of a second, that the position snapshots are to be taken.

For example,

{1} will record position information every 1/10 of a second

{5} will record position information at half-second (5/10) internals

{10} will record position information at 1 second (10/10) intervals

The system, after receiving a proper command, will reply by transmitting

[quote]{Captured @ X.Xs ticks[/quote]and will then transmit a stream of data similar to this one:

[quote]00:00.1 0
00:00.2 0
00:00.3 0
00:00.4 0
00:00.5 0
00:00.6 1
00:00.7 5
00:00.8 6
00:00.9 7
00:01.0 9
00:01.1 13
00:01.2 11
00:01.3 10
00:01.4 9
00:01.5 8
00:01.6 7
00:01.7 6
00:01.8 6
00:01.9 6
00:02.0 5
00:02.1 4
00:02.2 3
00:02.3 1
00:02.4 0
00:02.5 0[/quote]The system also contains two pushbuttons.

Pressing either of the buttons at the instant a snapshot is taken will result in the following data transfer

[quote]MM:SS.T P B1[/quote]or

[quote]MM:SS:T P B2[/quote]Where MM equals minutes, SS equals seconds, T equals tenths of a second and P equals the fader position.

[B]Stop Capture[/B]

To stop the capture, send the string

[quote]{*}[/quote]Which is an asterisk enclosed by curly braces.

The system will reply with

[quote]Stopped
}[/quote][B]Working with MediaLab[/B]

MediaLab v2006 has been programmed specifically to work with this fader system. The data transmitted by the Digital Analogue Slider is saved in a special text file, provided that the file

[I]comport.txt[/I]

is included in the same file as the experiment you're running. I've included a copy of a working comport.txt file below. Here's the text included in mine:

comPort, baudRate, parity, dataBit, stopBit
5,19200,n,8,1

'5' represents the serial port I'm using. This number may change, depending on your computer's hardware.

So basically, all you need to do is start the Digital Analogue slider immediately before you present the target video, picture or text. Then, stop the slider when the subject has finished viewing the information. The captured slider position data won't be included in the main data file generated by MediaLab. Rather, it is found in a separate text file called 'comdata.txt' which you can open and analyze using Wordpad, Word or any similar text editor.

If you have any questions at all, please reply to this thread.

Thanks!

John
Empirisoft Hardware