Using a laptop as a stim computer


This Wiki post is meant to collect information relevant to using a laptop instead of the dedicated MEG stimulus desktop computer.

  1. Projector
    The ProPixx projector requires a dual DVI-D input. VGA to DVI adapters don’t work. We have mini-DP to DisplayPort and DP to DVI-D adapters, but this will only allow 60 Hz at full resolution, while the projector supports 120 Hz. We also have a HDMI to DVI adapter, and this works. [needs to be confirmed for 120Hz]

  2. Response pads
    Access to the response pads is through the ProPixx Controller (projector) USB connection. The pads no not act as a keyboard. See this post for details.

  3. MEG triggers
    Triggers can be sent to the MEG in various ways.
    a) One is through the projector feature of encoding information in the color values of the top-left pixel of the display. The projector must be set to the proper “pixel mode” and at least one GPIO trigger defined in the MEG acquisition configuration (.rp file).
    b) Another is to use a USB to serial (DB9) adapter (we now have one) connected to the MEG Electronics Control Console (ECC). At least one serial trigger must be defined in the acquisition configuration.
    c) A third option would be to use a USB to parallel port (DB25) converter. However, cheap adapters that exist nowadays don’t work for this. They are only meant for printers and are not recognized as parallel ports (e.g. LPT1) in Windows. Some that would have worked are no longer available. Devices from EEG manufacturers are available but very expensive. The best option would then be to make an adapter ourselves. (There’s also a small possibility we could use a special driver from Bixolon with one of the cheap adapters, but we don’t have one to test.) Until then, best to use one of the other options above.

Note that the digital input options of the MEG may change with the upcoming new electronics.