Wet sponge electrode holders for Unicorn EEG system

This is a collection of 7 designs for sponge holders for adapting the Gtec Unicorn EEG system to be used with wet sponges as electrodes as documented on https://robertoostenveld.nl/unicorn-sponge-electrodes . All designs, except for number 1, are based on a standard Ag/AgCl EEG ring electrode that is also included in the models. I did not print or practically try out all the designs, but the last design "7" seemed to be quite practical. In the end, we discontinued these explorations in favor of a BrainProducts R-Net electrode cap. I printed the various designs using PLA and a Prusa Mk3s printer with a 0.25 mm nozzle.