Vibrations on a person’s skin were used to successfully send messages in English. This haptic technology from Purdue University was fueled by a challenged posed by Facebook.

“They wanted to know if it was possible to transmit messages and speech through the skin. We thought it might be possible, and we could give it a try,” says Hong Z. Tan, Purdue professor of electrical and computer engineering.

The smallest unit of sound is known as a phoneme. As the user speaks, each English phoneme is assigned to a certain vibration, which is played by the new device on the wearer’s skin. Thus, these signals can be decoded into user-friendly messages.

How does the assignment process work? Well, the research team encoded the device to play sensations for each distinct speech trait. For instance, as someone says a sound that is produced at the front of the mouth, such as a “p” or “b,” the wrist experiences vibrations. However, vibrations will be present near the elbow when sounds like “g” or “k” are spoken, which are formed at the back of the mouth.

Stationary vibrations were assigned to consonants, while vowels received moving sensations. The device generated a lighter vibration for an unvoiced consonant, such as a “p,” when compared to voiced consonants, like the letter “b.”

“In testing, we found that people never confused a consonant with a vowel because the sensations are distinct,” says Tan. “We start with a small group of phonemes, then we gradually train people up to 500 words. Everybody’s performance varies, but those who did really well acquired one English word per minute.”

After users learn how to decode which vibrations are associated with certain sounds and words, then the applications open for an alternative means of communication.

“From the beginning, I really wanted this technology to be a general communication project and to prove that information can be transmitted through touch,” says Tan. “People with sensory deficits need to be able to hear a car honking or the faucet running, so we can create a sensation specifically for that. Or, for example, if people are running, we can set simple messages to let them monitor their progress.”

The Purdue team hopes to expand this technology beyond English, including more languages and possibly adding stimuli from the environment.