Just to point out (again) that you don't need fancy equipment to do this. Connecting electrodes to the brain is unnecessary. Some simple external sensors† and hypnosis and you're good to go.

The basic idea is to set up simple binary signals between your unconscious mind and your sensors. This is trivial.

Then you can take e.g. eight data plus one clock and gang them together to make a simple parallel port between your brain and the computer. Easy. (The obvious thing to do is use eight fingers plus a thumb.)

The brain is already a hugely sophisticated information processing device. The problem is not to get the raw signal out of it and then decipher it. That's just pushing sideways on the train. Just use simple hardware and let the brain do the pre-processing to get legible signals (with the subjective perception of direct mind-to-screen typing, say.)

†Galvanic skin response, or these days use little IMUs in gloves to detect twitches. The signals you're generating are not subtle. Another thing, the brain already has a high-bandwidth output device: the face. These days it should be trivial to train a NN to read expressions and "micro-tics" from e.g. some HD cameras trained on your face, and co-evolve a protocol between mind and machine.

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Edit to add, you guys have seen "Forbidden Planet" right? Take heed of the fate of the Krell, design your tools well, raise no "Monsters from the Id"...