An open source EEG hardware project has existed for years in openEEG, Olimex sells a surface-mount version with enclosure for $100 (though it is only two-bipolar channels) https://www.olimex.com/Products/EEG/OpenEEG/
An open source EEG hardware project has existed for years in openEEG, Olimex sells a surface-mount version with enclosure for $100 (though it is only two-bipolar channels) https://www.olimex.com/Products/EEG/OpenEEG/