[solved] Sending triggers to Nexus Trigger Interface via serial port
Hi!
My name is Daniel and I'm currently working on an experiment with our new Nexus-32 eeg. As the title reveals, I'm having some problems with the triggers sent to the Nexus Trigger Interface (NTI) via serial port. Even your tutorial didn't help. I'm very new to OpenSesame so I'm probably doing several things wrong.
My first question is: Are there any differences between sending a trigger via parallel port and sending it via serial port (the answer is probably yes)? Do I have to change my python Code according to this setting?
try:
from ctypes import windll
global io
io = windll.dlportio # requires dlportio.dll !!!
except:
print 'The parallel port couldnt be opened'
and
global io
trigger = 1
port = 0x378
try:
io.DlPortWritePortUchar(port, trigger)
except:
print 'Failed to send trigger!'
Or do I have to use another .dll?
I'm sure, however, that the hardware is working correctly. I was able to send a trigger via HyperTerminal to the NTI and it worked properly. These are the settings I used in HyperTerminal (sorry for the german language version):
There is one last question ... ;-) I checked the port adress of the serial port with a tool called Bios Reader and it showed me the following adress:
So I guess that I have to use the port 0x3F8 instead of 0x378 in the python code, right?
As you see I'm quite confused and any help is appreciated ;-)
Best wishes,
Daniel
Comments
Hi Daniel,
Yes, the parallel and serial ports require entirely different approaches. Fortunately, the serial port is actually much easier to access, because it doesn't require the use of any external
.dll
libraries. You can simply rely on theserial
module. You can find some examples here:In your case, you might open the serial port with a script like this at the start of the experiment:
And then send a trigger like this (at some moment during a trial):
At the end of the experiment, you need to close the connection again (otherwise you may experience trouble running the experiment twice without closing OpenSesame):
Good luck!
Cheers,
Sebastiaan
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Hi Sebastiaan,
thanks a lot for your support. It works just fine!
Best wishes,
Daniel
now could any one help me i am using vspe
@meldiwiny
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Hi, New user... OpenSesame seems to be a great program. Thanks for sharing! I am trying to get the above in-line-scripting to send signals from OpenSesame to Biopac via a USB TTL Module (Black box toolkit).
I have tried the inlinescripting posted above. However, I am getting an error message:
TypeError exception message: unicode strings are not supported, please encode to bytes:""x01
Could someone advise? Many thanks in advance,
Gunnar
Update, solved but other problem arisen.
I tried changing the unicode to bytes, and it seems to have worked as far as the previous particular error message goes. This is the code for triggering now
1 exp.trig.write(0x31)
2 exp.trig.write(0x30)
However, I am not getting a new error message for the inline script controlling the port. I think it is row 3.
1 from serial import Serial
2 exp.trig = Serial('COM3', 115200)
3 exp.cleanup_functions.append(exp.trigger.close)
"in _getattr_ raise AttributeError(u´%s not found´ % var) AttributeError: trigger not found.
Any help would be appreciated, thanks in advance
Hi @Gunnar
The variable is called
exp.trig
, notexp.trigger
.As an aside, I suspect that this code is based on something that was written a long time ago, when you needed to attach variables as properties to the
exp
object in order to be able to access them in all scripts. However, this isn't necessary anymore, and you can just use the global variabletrig
. It won't make any functional difference, but it will make your code a bit cleaner.See also:
— Sebastiaan
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Hi,
thank you @sebastiaan
Appreciate it, I will try this when back in the lab.
Hi again and thanks again @sebastiaan .
I have tested this now and the error message about exp.trigger disappeared so that part is solved.
However, I still can't seem to activate the USB TTL Module to send triggers from the experiment. I suspect I am still using the wrong trigger numbers in the inline script , the TTL module is asking for two byte hex values (for instance, line 1 on the module uses dpin 2 and hex 01). How would this work with the exp.trig.write() command? I have tried ("01"), ('01'), (0x31) and (0x01). The ("01") asks to convert from unicode to bytes, the (0x31) doesn't return an error message (but nothing happens in terms of triggering)
Best regards,
Gunnar