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Ultracortex Mark 2

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  • Printer used: Makerbot Rep 2
  • Material: PLA

For M2-Frame Components

  • Resolution: Low (Faster)
  • Raft: Yes
  • Supports: Yes (even though this uses A LOT of extra material)
  • Infill: 100% (we want it sturdy)
  • Number of shells: 3
  • Layer Height: 0.3mm
  • Temperature: 235 C
  • Speed while Extruding: 45 mm/s (you may be able to increase this depending on how well tuned your 3D printer is)
  • Speed while traveling: 150 mm/s

For M2-Electrode-Mount Components

  • Resolution: Low (Faster)
  • Raft: No
  • Supports: No
  • Infill: 100% (we want it sturdy)
  • Number of shells: 3
  • Layer Height: 0.3mm
  • Temperature: 235 C
  • Speed while Extruding: 45 mm/s (you may be able to increase this depending on how well tuned your 3D printer is)
  • Speed while traveling: 150 mm/s

Spring Options

We are in the process of testing different springs to be nested

Spring 1 (tested)

McMaster-Carr > 1 9657K279 Steel Compression Spring, Zinc-Plated Music Wire, .500" L, .600" OD, .045" Wire, Packs of 12

Summary: The ~23 lb/in is too strong!

Spring 2 (tested)

centuryspring.com: Custom spring order of Part # B6-8

Summary: custom order... ~1 lb/in is too weak...

Spring 3 & 4 (untested, but potentially better)

Our working version of the headset uses Springs 1 & 2, but I would recommend trying the following instead:

Electrodes

Dry (spikey) electrodes to be installed in Ultracortex nodes with hair:

Dry (non-spikey) electrodes to be installed in Ultracortex nodes without hair (forehead, for instance):

Ear Clip electrode (for reference)

Nuts & Bolts for Connecting Electrodes

We use small stainless steel screws and hex nuts to fasten the FRI electrodes (listed above) to the 3D-printed electrode mount components & wiring that connects the electrodes back to the OpenBCI board. We used stripped Gold Cup Electrodes electrodes as the cabling, by removing the gold cup with a wire cutter and looping the exposed wire around the screw between the two tightened hex nuts (as seen in the picture below).

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Other Helpful Information

  • The following equipment/accessories were either necessary or very helpful in the assembly of this headset.
    • super glue
    • sandpaper
    • coarse flat & circular files
    • some sort of flexible wiring (terminating in a female header) to connect the electrodes back to the OpenBCI board. We used stripped Gold Cup Electrodes electrodes & stripped touch-proof connector cabling.
    • an exacto/razor blade
    • wirecutters
    • needle-nose pliers

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  • The "M2_Electrode Mount A_01" part has a small lip on the inside (where the spring fits into) that must be manually removed with an exacto/razor blade.
  • Most of the tolerances between pieces are too tight, so assembly requires substantial filing and sanding.
  • The "M2_Electrode Spacer_01" part is used to adjust for different head shapes and sizes
  • With this versoin (M2) we unfortunately only have one frame size, so this headset will not fit most heads, even with the spacers and springs.
  • Before printing, make sure to re-orient the frame STLs so the flat sides of the model are on the platform.

Photos of Ultracortex M2

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