Triggers from PsychoPy to triggerbox from brain products

Other
1

Good afternoon,

We are unable to get our triggers to work for our NIRSScout system by Brain Products. Our connection is the following:
Stimultation Windows laptop (running Psychopy) → USB cable → Brain Products TriggerBox → TriggerBox “Amp” output → BP-245-1565 → NIRScout trigger cable → NIRScout trigger input on the machine.

I see some queries about this on the forum but did not see a definitive solution. Can someone help us with this?

The code that Brain Products gave us is :

import serial
import time
import threading
Connected = True
PulseWidth = 0.01
def ReadThread(port):
while Connected:
if port.inWaiting() > 0:
print (“0x%X”%ord(port.read(1)))

Open the Windows device manager, search for the “TriggerBox VirtualSerial Port (COM6)”

in “Ports /COM & LPT)” and enter the COM port number in the constructor.

port = serial.Serial(“COM6”)

Start the read thread

thread = threading.Thread(target=ReadThread, args=(port,))
thread.start()

Set the port to an initial state

port.write([0x00])
time.sleep(PulseWidth)

Set Bit 0, Pin 2 of the Output(to Amp) connector

port.write([0x01])
time.sleep(PulseWidth)

Reset Bit 0, Pin 2 of the Output(to Amp) connector

port.write([0x00])
time.sleep(PulseWidth)

Reset the port to its default state

port.write([0xFF])
time.sleep(PulseWidth)

Terminate the read thread

Connected = False
thread.join(1.0)

Close the serial port

port.close()

2

Hi @swijeakumar,

could you surround the code example you share with triple backticks (```)? It will make it more readable. :slight_smile:
It would also be helpful if you were a bit more specific in what you mean by being unable to get the triggers to work. The code you pasted is a little hard to read, but it looks like it is defining a function to send triggers with - how do you use that function in your code, do you get any errors if you try to do so or no errors but also no recorded triggers?

3

Hi there,

We have run into a more specific and strange issue now - the first 20 or so triggers appear on our neuroimaging software and then no other triggers appear. I have pasted the code below. I could also send you my task if you could take a look or chat on Teams?

I inserted a custom code component in the Trial Routine and added the following bits of code to the different tabs:

Under ‘Begin Experiment’:

import time
import threading
Connected = True
PulseWidth = 0.5
            
# Open the Windows device manager, search for the "TriggerBox VirtualSerial Port (COM6)" # in "Ports /COM & LPT)" and enter the COM port number in the constructor.
port = serial.Serial("COM3")

def ReadThread(port): 
    while Connected: 
        if port.inWaiting() > 0: 
            print ("0x%X"%ord(port.read(1))) ```

Under 'Begin Routine':

```# Start the read thread
thread = threading.Thread(target=ReadThread, args=(port,))
thread.start()

# Set Bit 0, Pin 2 of the Output(to Amp) connector
port.write([0x01])
time.sleep(PulseWidth)

# Reset Bit 0, Pin 2 of the Output(to Amp) connector
port.write([0x00])
time.sleep(PulseWidth)```

Then I inserted a new custom code component at the very end of the experiment and added the following code under 'End Experiment':

```# Terminate the read thread
Connected = False
thread.join(1.0)

# Close the serial port
port.close()```

Any advice on what we are doing wrong would be massively appreciated.

Best,
Sobana
4

Hi @swijeakumar, sorry I respond after a delay. The issue you report now indeed sounds strange.
I never sent triggers in the same way as you do, so I may be of little help here, but I will try. :slight_smile: First of all I would try to see if sending the triggers through a python script gives you the same problem. So you could reformat the code snippet you pasted so that, for example, it sends one trigger every 250 ms, sending triggers from 1 to 255 (sequentially). If this fails (at some point) you will at least know: a) that PsychoPy is not part of the problem; b) how many triggers are received (the value of the last received trigger).