{"id":935,"date":"2022-03-04T11:58:57","date_gmt":"2022-03-04T16:58:57","guid":{"rendered":"https:\/\/courses.ideate.cmu.edu\/62-830\/s2022\/?p=935"},"modified":"2022-04-13T10:15:16","modified_gmt":"2022-04-13T14:15:16","slug":"haptic-feedback-feeling-the-dance-you-cannot-see","status":"publish","type":"post","link":"https:\/\/courses.ideate.cmu.edu\/62-830\/s2022\/?p=935","title":{"rendered":"Haptic Feedback: Feeling the Dance You Cannot See"},"content":{"rendered":"\n

A foot, planted firmly on the ground, slides backward. The knees bend and bend and push the feet against gravity and the stage floor. One foot releases and the toes curl and draw up the leg to the knee. The other, balancing on the toes. Arms, held tight in a circle, help the rest of the body rotate and rotate until gravity finds its way back. Both heels find the floor and the knees bend in release.<\/p>\n\n\n\n

Dance relies on the audience\u2019s sense of sight to experience a performance. However, dancing itself is a very tactile experience. A dancer\u2019s precise movements depend on a heightened internal awareness of the body \u2013 how joints are stacked and what muscles are activated. They must also maintain an awareness of external forces \u2013 how one limb moves in relation to the other, how their skin feels sliding against the floor, and where they sense other dancers moving with them in space.<\/p>\n\n\n\n

The experience of the audience is vastly different from that of the dancer. So is there a way to bridge this divide and communicate a multisensory experience to the audience, and allow those who cannot see, to feel? Tapping into this sense of touch might help audiences experience dance in a whole new way.<\/p>\n\n\n\n

The word haptic derives<\/a> from the Greek word \u201ctouch\u201d. Simply put, haptics is the coordination of touch, perception, and action. Together<\/a>, our skin, musculoskeletal system, and nervous system communicate information to our brains about the outside world we experience. These systems work together to make up our haptic sense<\/a>. Although one could classify any communication received via a tactile sensation as haptic feedback, it is most often used today regarding haptic technology that simulates the human touch experience.<\/p>\n\n\n\n

Haptic feedback is becoming more common in everyday technology as a communication tool between the device and the end-user. Apple is certainly a fan, with Macbook force touch trackpads<\/a> providing haptic communication for various degrees of force, or the Apple Watch<\/a> sending communication via haptic \u201cbumps\u201d to user’s wrists to tell them the time. Video game controllers are famous for their Dual Shock haptic feedback, rumbling the entire device during an intense boss battle. In newer, more sophisticated controllers, haptic feedback creates the sensation of a joystick<\/a> beneath the player\u2019s thumb by using precise vibrations.<\/p>\n\n\n\n

How does it work?<\/strong><\/p>\n\n\n\n

Haptic feedback relies on two systems<\/a> to engage the haptic sense \u2013 one on the human side and one on the machine side. Each requires an input, a translation, and an output.<\/p>\n\n\n\n

On the human side<\/a>, a finger\u2019s skin cells make contact with a haptic feedback device and receive an input. This alerts the finger\u2019s tactile sensor nerves which send whatever information it just received from the cells to the brain. The brain translates this information and neuron synapses fire a call to action to the body. This output might be a sudden jerk if the haptic feedback is programmed to feel sharp<\/a>, or its denseness may make for curious fingers to explore the larger shape.<\/p>\n\n\n\n

A similar process happens on the machine side<\/a>. Haptic feedback sensors receive an input, either data that has been programmed or some external force, and send it to a computer. The computer then translates this data as commands to actuators, the machine\u2019s device that produces motion. Based on the data it receives, it outputs specific vibration frequencies, too high pitched for the human ear, to exert different levels of force, motion, and sensation.<\/p>\n\n\n\n

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Figure 1 from Sreelakshmi and Subash, \u201cHaptic Technology.\u201d<\/em><\/figcaption><\/figure>\n\n\n\n

In this way, haptic feedback can simulate touch and trick the brain into firing neuron synapses that make us think we are experiencing a surface different than how it appears to exist in the real world. Our haptic sense is incredibly sensitive<\/a> and can detect and perceive thousands of surface textures, an object’s directional motion, velocity, and temperature. This sense is so delicate, that one spike from a single touch receptor neuron is enough to elicit conscious recognition in the brain<\/a>. This allows for precise applications of haptic feedback to simulate texture and 3D objects. <\/p>\n\n\n\n

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