DirectRT with Cedrus StimTracker (case 22798)

I've currently setup a Cedrus StimTracker to send TTL signals from my stimulus presentation computer to a Neuroscan NuAmps EEG amplifier to mark events. The Cedrus Stimtracker has a USB connection, but emulates a serial port connection (for more information, see here: [URL]http://cedrus.com/support/stimtracker/tn1403_install_usb_win.htm[/URL]). I've verified the Stimtracker device is working properly by sending signals using RealTerm (similar to Hyperterminal) from the stimulus machine to the EEG recording software. Markers are showing up perfectly. However, I'm having difficulty sending TTL signals from within DirectRT (i.e., the IOtest utility). The problem is that DirectRT seems to require a decimal port address to send the TTL. Since the Cedrus box creates a virtual serial port (COM 3 on my system), there is no hardware port address (there is no resources tab for the port in device manager, per these instructions: [URL]http://www.empirisoft.com/support/showthread.php/8808-COM-port-address-for-USB-to-serial-converter-(case-17709)[/URL]. I have tried using port 1000 (which to my knowledge would be the decimal address of COM3), but this doesn't work. I'm wondering if you know of a way to find the appropriate port address for the virtual serial port, or if there is an alternative workaround that will allow me to send TTL triggers using DirectRT. Thank you.


Robert Goodman

Please tell me the full version number (i.e., 20xx.x.xxx) of your copy of DirectRT. You can find it by opening DirectRT and selecting Help>About DirectRT from the main menu bar.

Hi Jason,

My Version number is: 2014.1.123. Thanks for the prompt response.

Best,

Rob

Rob,

Using DirectRT 2014, set up a DirectRT .csv input file to send ttl signals as normal (see [url]http://www.empirisoft.com/directrt/help/directrt_samples_of13_ttl_signals.htm[/url]). It doesn't matter what you type for the port address in the loc cell or the number in the time cell after the stim cell with ttl: in it.

This is because you will include a .txt file named comport.txt in the same folder as the .csv input file you create. DirectRT 2014 will ignore the values in the loc and time cells as long as the comport.txt file is in the same file folder as the .csv input file that wants to send ttl signals.

When you create your comport.txt file, you will need to define the the proper number to reflect the comport you want the computer to use to send the ttl signal; I've attached an example comport.txt file to this email. This is based off of the same functionality in MediaLab used for sending and receiving data over serial ports (for an explanation and example of the comport.txt file see [url]http://www.empirisoft.com/medialab/help/miscellaneous_features.htm[/url]).

Give this a try and let me know how it goes or if you have any questions.

Jason

Make sure you have DirectRT version 2014.1.111 or later.

Hi Jason,

I'm attempting to send TTL signals to the Cedrus Stimtracker using the method you've suggested, but unfortunately they aren't registering. I'm using the SendTTL.csv example file (unaltered) for testing purposes, and I've added the Comport.txt file in the same directory as the .csv file being run. I've verified the port settings of my virtual COM port under device manager and mirrored these settings in the comport.txt file (attached). I've also tried changing the comport in the comport.txt file to "1" based on what I have read in a previous thread that addresses a similar issue ([URL="http://www.empirisoft.com/support/showthread.php/8739-ttl-signals-vs-sending-receiving-serial-data-(case-15992)"]here[/URL]). No dice. Any suggestions for next steps?

Thank you so much for your help with this.

Best,

Rob

What happens if you add key mappings to your comport.txt file instead of using the 0,0 value?

Hi Jason,

Still no triggers sent when adding key mappings

Hi Jason,

I'm still unable to send TTL triggers using DirectRT. I spent most of the afternoon yesterday reading up and testing various versions of the comport.txt file (including adding the key mappings, changing the com port, baud rate, etc.). If you have any suggestions regarding how to troubleshoot this problem I'd greatly appreciate it.

Best,

Rob