Lumina LSC-400B trigger

1

Hello,
We’re using a Lumina LSC-400B controller (ASCII mode) with a serial-to-usb adapter to our stimulus machine and been having some issues with picking up triggers and responses from the cedrus response box in psychopy.
Is there a way to set up the controller to emulate a keypress that can be picked up by psychopy?
Thanks in advance,
Darya

2

The LSC-400B was superseded over 10 years ago by the newer Lumina 3G controller.

See this LSC-400B support note, Connecting to the fMRI Scanner’s Trigger. By setting a couple of switches, you can have the controller detect fMRI scanner triggers that are much shorter in duration. This will still not work if the controller is in “Lumina” mode because the controller is too slow for that mode, but you are using the ASCII mode anyway.

The LSC-400B cannot emulate a keyboard keypress; the newer Lumina 3G controller does have a built-in Keyboard mode.

Last tidbit: what serial-to-usb adapter model are you using? the only one we recommend is the USB-COM-U13 from Saelig.

3

Thanks for your response.
I’ve managed to pick up a trigger to start my task using pyserial. We’re using a goobay usb-to-serial adapter with a mac OS.
I’m still unable to record button presses on Lumina LS-pair as it seems to interfere with stimulus presentation. I saw here that using xid I should be able to log presses more accurately - is this possible to do with LSC-400B?

4

If you use XID commands directly, you can get time-stamped keypress information. But scanner triggers will not come through if you are using the built-in pulse extender that I mentioned earlier.

If you get the Saelig adapter, you will be able to use our pyxid2 library instead of handling the XID commands directly, and get better timing.

5

Can I use the XID commands with the controller set to ASCII mode? (in which case getting the scanner trigger seems to work)

6

No. The XID commands work only when the controller is in Lumina mode.

7

Hi Darya,
How could you use pyserial to pick trigger up from scanner using psychopy? Could you share your experience?
I just need start/synchronise my psychopy stimulus with MRI scanner, my task doesn’t have user response.
Thanks in advance
Bruno

8

Hi Bruno, are you using a Lumina controller? if so, which model?

9

Hi Hisham,
We have the lumina LSC-400b. My psychopy stimulus is very simple, and I just want to trigger the start of fMRI dynamics with the start the psychopy stimulus, I don’t have to register button response or anything else. I use a notebook with Windows and I already installed the driver for serial-usb connection. I just want to transform a TTL pulse from Philips Achieva scanner into a signal that my psychopy task recognizes.

10

This could be one of two things:

  1. It is possible that the controller is not detecting the TTL pulse from the Philips Achieva. Please see this page. The bottom line: does the Trigger LED light up on the controller when a scanner trigger is expected?

  2. If the Trigger LED is lighting up, the next step is to see why PsychoPy is not detecting the trigger information sent by the controller. Are you using our pyxid2 library?

11

The “forum post” are indexed to itself post. Are you referred to this post: Connecting to the fMRI Scanner’s Trigger ?

  1. Not all pulses, I will try to change the Trigger Sensitivity to try improving the detection based on this post:Connecting to the fMRI Scanner’s Trigger . This is my first challenge :slight_smile:
  2. I’m very dummy in signal detection issues. I don’t know how to use pyserial or pyxid2 library or other library in my psychopy code. For this I sent my doubt here, because I see on this post that Darya could do that. I don’t know how to start to put a code inside my psychopy task to detect the serial signal from lumina lsc400b. My psychopy task is already trigged with the “T” key and we already use it in another site that has the Lumina 3G, that already has the keyboard mode built in. So I want to do the same thing in the site that has LUMINA LSC400b. Could you send me some reference or some tips that I could use this pyxid2 library in psycopy structure ?
12

Thank you for bringing the circular link to my attention. I fixed it.

Please see this support page for PsychoPy. We cannot offer support beyond that – sorry.