Tactile feedback allows devices to communicate with users when visual and auditory feedback are inappropriate. Unfortunately, current vibrotactile feedback is abstract and not related to the content of the message. This often clash-es with the nature of the message, for example, when sending a comforting message.
We propose addressing this by extending the repertoire of haptic notifications. By moving an actuator perpendicular to the user's skin, our prototype device can tap the user. Moving the actuator parallel to the user's skin induces rub-bing. Unlike traditional vibrotactile feedback, tapping and rubbing convey a distinct emotional message, similar to those induced by human-human touch.
To enable these techniques we built a device we call soundTouch. It translates audio wave files into lateral motion using a voice coil motor found in computer hard drives. SoundTouch can produce motion from below 1Hz to above 10kHz with high precision and fidelity.
We present the results of two exploratory studies. We found that participants were able to distinguish a range of taps and rubs. Our findings also indicate that tapping and rubbing are perceived as being similar to touch interactions exchanged by humans.