Multiple runs of experiment in serial order, get BOARD_NOT_CREATED_ERROR:15 when second run is set to run

[sjburwell]

Hello and thank you for the wonderful library and documentation.

I am trying to run multiple runs of the same ERP experiment in serial order in the same Python script and running into board connectivity issues. For example, in my script that I've adapted from the getting started:

## run_rsvp_script.py
# ... initiates board, subject, session, etc. info
visual_rsvp.present(duration=record_duration, eeg=eeg_device, save_fn=save_fn) # 1st run, works fine
visual_rsvp.present(duration=record_duration, eeg=eeg_device, save_fn=save_fn) # 2nd run, errors

The below error message which is printed during the 2nd run (after I press spacebar to the instructions) suggests that the board is not ready or accepting connections, however, the EEG "subscription" appears to have been stopped appropriately in the first run (i.e., eeg.stop() has been executed).

28.4987         WARNING         Couldn't measure a consistent frame rate.
  - Is your graphics card set to sync to vertical blank?
  - Are you running other processes on your computer?

28.5264         WARNING         t of last frame was 28.04ms (=1/35)
Traceback (most recent call last):
  File "run_rsvp_script.py", line 29, in <module>
    visual_rsvp.present(n_trials=20, eeg=eeg_device, save_fn=save_fn, block=2) #block)
  File "/Users/burwell/Documents/eeg-notebooks/eegnb/experiments/visual_rsvp.py", line 76, in present
    eeg.start(save_fn, duration=record_duration)
  File "/Users/burwell/Documents/eeg-notebooks/eegnb/devices/eeg.py", line 276, in start
    self._start_brainflow()
  File "/Users/burwell/Documents/eeg-notebooks/eegnb/devices/eeg.py", line 215, in _start_brainflow
    self.board.start_stream()
  File "/Users/burwell/anaconda3/envs/eeg-notebooks/lib/python3.7/site-packages/brainflow/board_shim.py", line 843, in start_stream
    raise BrainFlowError ('unable to start streaming session', res)
brainflow.board_shim.BrainFlowError: BOARD_NOT_CREATED_ERROR:15 unable to start streaming session

Any suggestions would be greatly appreciated.

Best,
Scott

[sjburwell]

✅ Found a workaround, needed to wrap the EEG() and generate_save_fn() into a loop to generate multiple runs. ✅