There's also a device consisting of an electrode array for the tongue to attempt to provide an additional sense: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5

There's also a device consisting of an electrode array for the tongue to attempt to provide an additional sense: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5523951/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5523951/ "Tactile Vision Substitution (TVS) was the initial motivation for designing the TDU. With TVS, a user-controlled video camera captures a real-time image from the ambient environment and provides a spatially-corresponding tactile stimulation to the user’s skin."