Mssing Triggers

[ReneS]

Hey,

We are currently setting up a new EEG Lab using the BIOSEMI system. For that we are using a Linux PC with MATLAB/Psychtoolbox as stimulus computer and Windows 10 as Recording computer (ActiView 806 installed).

Sending triggers from the Linux computer via the BIOSEMI USB trigger cable works fine, we tested this using a Blackbox toolkit. All the triggers send get recorded as normal. However, when we connect the USB cable to the USB receiver (and the windows 10 computer) the triggers won't show up in the ActiView software.

Any ideas why that could be?

Kind regards,

Rene

[Coen]

How did you establish that you are actually sending triggers when you do not see them in ActiView ?

Best regards, Coen (BioSemi)

[rahulag801]

Hi Coen,

I am working with Rene on this problem. We are using blackbox toolkit (BBTK) system which confirms that Biosemi USB trigger Interface cable send trigger signals to blackbox toolkit system. We are using matlab to send triggers (serial port) to BBTK.

When we send trigger signals to ActiView software we cannot see the trigger.Although when we manually send triggers using F1, & F2 etc. we can see it on the ActiView software.

Any idea what is happening?

I apologize for delay in response

Regards,
Rahul

[Coen]

The blackbox toolkit (BBTK) system has a 25-pole TTL input connector. Did you actually make a 37 to 25 parallel cable ?

Test the trigger port on the USB-receiver as described in post 4 in viewtopic.php?f=1&p=3615#p3615 (short pin 1-16 to pin 37). If the port responds OK, then you are still not actually sending triggers to the 37-pole plug on the USB trigger interface (confirm with voltmeter or oscilloscope).

Make sure your triggers are longer than the sample period (e.i. > 0.5 ms on 2 kHz)

Best regrads, Coen (BioSemi)

[ReneS]

To answer your question: Yes, the guys from BBTK specifically made a 37 to 25 parallel cable for us, as we asked for a way to test a setup with the Biosemi system.

To the problem at hand:
I tested USB receiver as asked today and everything seems to be in order. When the cable is disconnected all pins are high, and as soon as I short either of the 1-16 pins to pin 37 the corresponding pin goes to low.
I also checked that the RespSwitch setting in the CFG file is set to 0.

We tested sending the triggers with the I/O port function by psychtoolbox as well as the BioSemiSerialPort function made by Roee Gilron and suggested by Cortech ( https://cortechsolutions.com/ufaqs/can- ... wo-system/ )

As I said earlier, we are able to register the triggers with the BBTK (using the extra cable) without time delay.

Do you have any more ideas?

Regards
René

[Coen]

There might be a bad ground connection (pin 37). Check as follows:

Disconnect the USB cable from the USB-trigger interface. Plug just the USB-trigger interface (without USB-cable) into the USB-receiver and confirm that all triggers 1-16 change from HIGH to LOW.

Best regards, Coen (BioSemi)

[ReneS]

Hello again,

we checked what you asked, and all triggers change from high to low.

Kind Regards,
René

[Coen]

Your tests prove that the BioSemi hard- and software is working correctly. Email you trigger generation program to info@biosemi.com.

Best regards, Coen (BioSemi)

[Coen]

Your trigger generation software seems OK: we see the triggers all perfectly in ActiView.

Please confirm: did you (also) test with just the USB trigger interface connected to the USB-receiver ? So, without any other connection to the USB trigger interface (such as a splitter cable with connection to the BBTK).

Best regards, Coen (BioSemi)

[ReneS]

Yes, except one time, we always tried to get the triggers into ActiView with only the USB trigger interface connected to the USB receiver (without the BBTK cable inbetween).

We will next try to set up Laptop with the ActiView software and connect it to the USB receiver, just to confirm if it is a general issue or if it is specific to the lab computer.

Regards,
René

[ReneS]

Hey,

we tried getting triggers on a different computer, but still no luck.
Do you think it might help to try it with a Windows 7 computer? Or do you have other ideas?

Regards
René

[Coen]

Please sent the USB-receiver and trigger interface to BioSemi to check the hardware.

Best regards, Coen (BioSemi)

[rahulag801]

Hi Coen,

Can you please share your email ID with us. We can discuss about sending the items to Biosemi.

Best Regards,
Rahul