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-   -   Stim Tracker to ADInstruments’ PowerLab using Math Lab (http://community.cedrus.com/showthread.php?t=1844)

psycit@vuw.ac.nz September 17th, 2013 06:11 PM

Stim Tracker to ADInstruments’ PowerLab using Math Lab
This is with reference to the discussion on http://community.cedrus.com/showthread.php?t=1299

I hope to clarify what is happening when you send the command 'mh' from math lab using ADInstrument Powerlab as a recording mechanism.

have a look at the link http://cedrus.com/support/stimtracke...4_powerlab.htm
It shows you that bit 6-8 is the event marker 0-2 which gives you a value of 1-7(3 bits) trigger to play with. Keep in mind the location of the bit (6-8) which has a byte value of 32 onwards.

Going back to the command 'mh' which is standard on Stim Tracker you can send the command like "mh" + byte value which will correspond to which ever bit is on.
Example: sending the command ('mh',1) will set bit 6 on in the AD instrument giving the value 32 (byte) in the lab chart software.
Example: sending( 'mh',7) will set all the three bits on (6-8) which will give a digital byte value of 224 in the lab chart.
Note: take note that this values are only the bit 6-8 any bit on from 1-5 will affect the digital byte on the Labchart event.

it took us a while to figure out what's happening and just wanted to share out results because I also get some information in lots of forum.:) I am sure it will be the same principle in most computer languages.

Any question and clarification you can reply or not sure if you can access our email address here.:D



Hisham September 18th, 2013 09:00 AM

Thank you!

psycit@vuw.ac.nz October 8th, 2013 03:26 PM

Hi Hisham

Just wondering is their more commands that can be used apart from mh and mp in StimTracker?
beside from http://www.cedrus.com/support/stimtr...t_commands.htm

Right now I understand base on Ads instrument http://www.cedrus.com/support/stimtr...4_powerlab.htm I can only use Bit 6-8 for event triggering?



MonikaT October 14th, 2013 09:57 AM

Hi Al,

All the commands available are listed on the webpage you mention.

Hisham October 21st, 2013 05:29 PM

Al, you are unfortunately correct: only bits 6-8 can be used for sending event codes. More event code bits are available when the EEG’s input accepts 16 bits, but AD Instruments’ PowerLab accepts only 8 bits. We limited event codes to three bits to leave room for the other signals: light sensors, audio, microphone/voice key, and participant input.

psycit@vuw.ac.nz November 4th, 2013 12:46 PM

Hi Hisham and MonikaT

Thank you for the clarification.
What we did as a work around which others may be doing as well is that we used the other one light sensors to add 1 bit in the event giving us at least 4 bits to play with on trigger at any case it's just a matter of putting a shape where the light sensor is located and we can trigger one light sensor bit.

if in case we will not use the two light sensor we can even use two additional bits, just an advise also for those would like to add some event trigger options which is handy on multiple conditions being monitored at times.



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