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Frequently Asked Questions

How do I improve my calibration accuracy?

First, open the signal viewer by pressing 0 in the main menu to check the quality of the EEG signal. If the reported noise to signal ratio is high, try to reduce the noise as follows:

  • Make sure your headset is properly set up and fitted. See our instructions here: :ref:`fittingRef`.
  • Move away from wall outlets, plugged in electronic devices, and other potential sources of line-noise.
  • If possible, place the amplifier behind you so your body is between the machine running the mindaffcetBCI and the amplifier.
  • Place the EEG hardware close to or on your body and run the electrode cables over your back.
  • Check all the connections between the electrodes in your headset and the amplifier.

Second, make sure that you have followed our OS Optimization instructions: :ref:`osoptRef`, and you are running the BCI in fullscreen mode: :ref:`fullscreenRef`. If the issue still remains you may have to dive deeper in the timing stability of your system. To do this we provide tutorials on:

  • :ref:`optobuildRef`
  • Building a trigger circuit
  • :ref:`triggercheckRef` Analysing your opto and trigger data

My calibration accuracy is fine but prediction mode does not work.

  • Add more calibration trials to the model by running the calibration sequence multiple times, or change the ncal argument in the online_bci.json configuration file (or the config file you are currently using).

  • Run the BCI in always full-screen mode: :ref:`fullscreenRef`

  • Inconsistent frame timing between calibration and prediction can cause this issue. To check the frametime stability of your system follow our tutorials on:

    • :ref:`optobuildRef`
    • Building a trigger circuit
    • Analysing your opto and trigger data

I'm getting an Acq did not start correctly and/or a brainflow.board_shim.BrainFlowError message.

  • Check if your amplifier is turned on and --if needed-- the usb-dongle is plugged in.
  • When using an OpenBCI amplifier with the WIFI-shield, make sure it is connected to the same wireless network as the machine running the mindaffcetBCI.
  • Check you serial port settings as described in the :ref:`COMref` section of the installation instructions.

How do I run the BCI in full-screen mode?

To run the BCI in full-screen mode set the fullscreen parameter in the onlin_bci.json configuration file --or in any other .json config file you are currently using-- to true.

Can I use the mindaffectBCI without an EEG acquisition device?

In some scenarios it is useful to run the BCI without having to connect an amplifier that's streaming real brain data (e.g. debugging/developing other components of the BCI). To run the full BCI stack (i.e. hub, acquisition, decoder and presentation) with a fake data stream, launch it with the debug.json config file:

python -m mindaffectBCI.online_bci --config_file debug.json

Alternatively, do run full decoder stack (i.e. hub, acquisation and decoder) without presenation use:

python -m mindaffectBCI.online_bci --config_file fake_recogniser.json

When using the fake data stream, calibration and cued prediction performance will be 100%. In Free Typing mode selections are made randomly.

I'm getting a framework not found error on Mac OS

On mac-os Big-Sur there is a known issue with older versions of pyglet see here. The solution is to ensure you are running pyglet 1.5.11 or higher. You can directly update your pyglet install with: pip3 install --upgrade pyglet

I'm getting poor performance on linux

As we are a small team, we have decided to focus our development and testing effort mainly on Windows PCs. We have tested the BCI on linux and mac-os, and it technically works. However, as mentioned here :ref:`triggercheckRef` it is also important that the screen redraws be accuratly time-stamped. In our testing on linux this time-locking was less robust than with an optimized windows installation. We believe this is can be addressed by a correct graphics system configuration, but have not identified it as yet. We would welcome feedback from the community about how to setup linux better.