A. Measuring bimanual pen movements using 1 computer, 1 tablet, 2 pens

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An example study comparing symmetric and asymmetric bimanual movements is:
Volman MJ, Wijnroks A, Vermeer A. (2002). Bimanual circle drawing in children with spastic hemiparesis: effect of coupling modes on the performance of the impaired and unimpaired arms. Acta Psychologica, 110, 339-356.

Download Video (WMV format, 6.9 MB) 2PN.wmv

Equipment

Simultaneous recording with two Wacom Intuos or Intuos2 pens on one Wacom Intuos and Intuos2 tablet is possible. Available tablet sizes are 8"x6", 12"x9", 12"x12", 18"x12". In theory, a tablet PC using the Intuos2 technology would also work.

Wacom Intuos 3, Graphire, or Bamboo tablets do not support 2-pen recordings. When using Wacom Intuos3 and later, see 2-tablet solution below.

You can quickly check whether your tablet and driver support 2 pens in MovAlyzeR by recording the tablet pen while moving the tablet mouse. An elaborate 3D-like area should appear in the recording window.

Setup

(1) Use Wacom driver downloadable from www.wacom.com:
6.1.0-6 for XP/Vista
Do NOT use the latest Wacom driver, e.g.:
6.1.5-3a for USB Tablets on Windows 7, Vista or XP (32 & 64 bit),

(2) In the Wacom driver, set the highest sampling rate in the tablet driver program (e.g., via All Programs or Control Panel), e.g., 200 Hz (= Recognition Rate)

(3) In MovAlyzeR, Rightclick your experiment >Properties >Running Experiment >Drawing options
Change Line Thickness into None.
(The two pens are sampled alternatingly. MovAlyzeR will draw lines between them creating complex areas. The lines need to be suppressed. So plot only the sample points alternatingly.

Recording

Instruct participant to keep both pens in proximity of the tablet (<1 cm) during the recordings.

When one pen approaches the tablet recording begins for that pen. Delay Recording Till Pen Touches Tablet needs Unchecked as it is checked by default.

When the second pen approaches the tablet, its coordinates form every other sample while the pen pressure for the second pen is still 0.
The pens are sampled alternatingly at 200 Hz (so 100 Hz per pen) throughout the period that both pens are near the tablet.

The raw data (HWR) file will look as follows. Here 1 refers to Pen 1 and 2 refers to Pen 2. Pen 2 touched the tablet first.
Code:
01 | x2 y2 z2   <== Pen 2 touches tablet starting recording. Only Pen 2 is recorded at 200 Hz. Pen 2 is out of proximity of the tablet 
02 | x2 y2 z2
03 | x2 y2 z2
04 | x2 y2 z2
05 | x1 y1 z1   <== Pen 1 gets in proximity of the tablet. Now Pen 1 and 2 are sampled alternatingly at 100 Hz each.
06 | x2 y2 z2
07 | x1 y1 z1
08 | x2 y2 z2
09 | x1 y1 z1
10 | x2 y2 z2
11 | x2 y2 z2   <== Pen 1 gets out of proximity of the tablet. Now only Pen 2 is sampled at 200 Hz.
12 | x2 y2 z2
So first 4 samples of Pen 2 are recorded at full sampling rate (because Pen 1 is still lifted beyond proximity).
Then 3 alternating samples (note that the sampling rate of each sample is half).
Then 2 more samples of Pen 2 at full sampling rate (because Pen 1 is lifted again beyond proximity).

When both pens are in proximity of the tablet (<1 cm), recording when recording starts

It is not predictable which pen forms the odd samples and which pen the even samples. Location information must be used to distinguish between the 2 pens.

Processing

MovAlyzeR does not (yet) have extra facilities to process 2-pen recordings. However, it should not be difficult for the user to integrate specific facilties.

The data of one pen can be selected for processing by MovAlyzeR's external applications (e.g., Matlab scripts or Batch job).
For example, copy the left pen to file EEEGGGSSSCCLnn.HWR and the right sample to EEEGGGSSSCCRnn.HWR.
Or, copy the samples closer than, say 1 cm from the closest of the previous two samples to one file and and the other samples to the other file. You still need to make an estimate which signal is which.
Here EEE, GGG, SSS are experiment, group, and subject code, resp.
CCR and CCL are two conditions that are set processing only (in the Word Segmentation options).
nn is the trial nr (01, 02, ...).

To ensure synchronization between the two files, fill in missing samples at the beginning of the recording. The number of samples is half of the number of unpaired samples. For example in the above sample there are 4 unpaired samples (at 200 Hz). So, this should have been 2 pairs of 2 samples (at 100 Hz). So replace Sample 02 and 04 by the first known sample of Pen 1 : Sample 05


B. Measuring bimanual pen movements using 2 tablets on 2 computers each running MovAlyzeR connected via a file sharing LAN network.

Setup

The 2 computers can be synchronized via an external app, e.g., one that writes a trigger file and the other that detects the trigger file.

In the Master computer (that triggers the other computer) you could have a poor man's trigger mechanism using a COMMON network drive and directory. I tentatively use n:\dir.

(1) In the Master computer rightclick each condition >Properties>External Apps.
Define under External Processing for the Event=Ready to Begin Recording
the following Batch job (e.g., master.bat):
__________________________________
echo Start Recording >n:\dir\start.txt
__________________________________

(2) For EACH group, define a GroupMaster and a GroupSlave.

(3) Export the Experiment from the Master and import it in the Slave computer.

(4) On the other computer (Slave) you do as in (1) but you define a different batch job.
(This job will loop and consume 100% of the CPU. Do not let this sit for an extended period).
__________________________________
:checkagain
if not exist n:\dir\start.txt goto checkagain
delete n:\dir\start.txt
__________________________________

(5) Then you define a Subject in both computers.

(6) Add the Subject to the GroupMaster in the Master computer en to GroupSlave in the Slave computer

(7) Start MovAlyzeR >Rightclick our subject >Run experiment (on Master AND on Slave computers)

(8) Check that you get the pause in the Master AND in the Slave computers.
If you need to debug, append
pause
to both .bat files.
When you see no errors, remove the Pause line in both jobs.

GLITCH: This might not work when Device=Mouse

For help on batch: Start >Run >cmd) and type help or search the internet.