Zachary Howard hat sich eine Synästhesie-Maske gebaut, auf Instructables gibt's 'ne Anleitung zum Selberbasteln. Das Ding ermittelt mit 'nem Sensor die RGB-Werte der Farbe irgendeines Dings, in der Maske werden die RGB-Werte dann mit servo-gesteuerten Ventilatoren in Gerüche umgesetzt.
You can think of the Synesthesia Mask as a smell pixel. Analogous to the way that pixels combine varying amounts of red, green, and blue to make different colors, the mask dispenses proportional amounts of a "red", "green", and "blue" scent to match the color you are touching. In practice a fan from one end of the scent manifold blows air over the test tubes containing our "red", "green", and "blue" smells. Each servo angles its test tube cover directing air down into the test tube where it picks up the scent of the essential oil inside. The "red", "green", and "blue" smells mix together and are then blown by the fan on the other end of the manifold into your mask. The amount of each scent that gets blown into the mask is mapped to the red, green, and blue color value being read by the color sensor on your hand.