Learning the Vibrotactile Morse Code Alphabet

Abstract

Vibrotactile Morse code provides a way to convey words using the sense of touch with vibrations. This can be useful in applications for users with a visual and/or auditory impairment. The advantage of using vibrotactile Morse code is that it is technically easy to accomplish. The usefulness of tactile Morse code also depends on how easy it is to learn to use without providing a visual representation of the code. Here we investigated learning of the vibrotactile the Morse code alphabet without any visual representation of the code and whether the learned letters can immediately be used to recognize words. Two vibration motors were used: one was attached to the left arm (dots) and the other to the right arm (dashes). We gave the participants a learning session of 30 minutes and determined how many letters they had learned. All participants managed to learn at least 15 letters in this time. Directly afterward, they were presented with 2-, 3-, 4-, or 5-letter words consisting of only the letters they had learned. Participants were able to identify words, but correct rates decreased rapidly with word length. We can conclude that it is possible to learn vibrotactile Morse code using only a vibrotactile representation (15 to 24 letters in 30 minutes). After the learning session, it was possible to recognise words, but to increase the recognition rates extra training would be beneficial.