**6. Haptics and games for the visually impaired**

Although haptics has proven to be a valuable technology to help gamers to have more immersive and realistic experiences, there is yet another type of game for which haptics is of essential value. Haptics is a very well suited type of interaction to address the problem of accessibility to games for the visually impaired.

There a currently different technologies that have improved the accessibility of electronic media to the blind people, such as automated reading software, voice synthesis, tactile displays with Braille and speech recognition. Yet, those are mostly focused in input/output of text and there is still some types of media that are still difficult to represent in a nonvisual modality, particularly graphics (2D or 3D), which form the basis for any computer game. Computer haptics seems to be a suitable solution for this problem of game accessibility, but still there are plenty of problems and research to be done on the field. It is hard enough to have an accurate haptic representation of an object in a virtual world that can be properly recognized by someone who is not able to look at it, and even harder to do it for the multiple objects and events that need to be perceived during game play. In fact, in most instances the haptic interface must be accompanied by some audio feedback as a complement, as to no overload the user with haptic signals (Yuan, 2008).

There have been two main approaches to enable visually impaired individuals into computer games. The first one is to design games that are inherently designed and implemented with the purpose of not relying on visual feedback. That is games whose playability is completely subject to interaction based on audio or haptic clues.

enables a high degree of control over the vibration motors of the device. On the software side, they provide MOTIV Integrator for OEMs to include in their devices a vibration profile manager that leverages on TouchSense, and MOTIV Software Development Kit to enable developers to build third party applications and video games that also take advantage of the

Another approach has been taken by Senseg, a company based in Finland whose latest haptic rendering solution is a promise to revolutionize the way we perceive computer generated haptic feedback on touch screens and other real world surfaces. Their E-Sense Technology is based on biophysics; where instead of having the device's surface vibrate, they create a sensation of vibration directly in the finger's skin by using an ultra-low electrical current from an electrode to produce a small attractive force. The modulation of that force allows the production of any number of touch sensations that can range from vibrations, clicks, textured surfaces and more. A direct implementation of this technology is in the mobile device industry, and the provided software APIs would allow the development of video games with a sophisticated array of touch sensations (Senseg, 2011). In terms of evaluation of the effectiveness of the haptic feedback on mobile gaming, Chui Yin Wong and peers tested the playability of a mobile game, using a vibrotactile feedback soft keypad, against playing the same game with a hard physical keypad. According to their findings, although players had higher scores using the soft keypad, they reported a preference on using the hard keypad in term of a better experience in the game play (Chui

Although haptics has proven to be a valuable technology to help gamers to have more immersive and realistic experiences, there is yet another type of game for which haptics is of essential value. Haptics is a very well suited type of interaction to address the problem of

There a currently different technologies that have improved the accessibility of electronic media to the blind people, such as automated reading software, voice synthesis, tactile displays with Braille and speech recognition. Yet, those are mostly focused in input/output of text and there is still some types of media that are still difficult to represent in a nonvisual modality, particularly graphics (2D or 3D), which form the basis for any computer game. Computer haptics seems to be a suitable solution for this problem of game accessibility, but still there are plenty of problems and research to be done on the field. It is hard enough to have an accurate haptic representation of an object in a virtual world that can be properly recognized by someone who is not able to look at it, and even harder to do it for the multiple objects and events that need to be perceived during game play. In fact, in most instances the haptic interface must be accompanied by some audio feedback as a

There have been two main approaches to enable visually impaired individuals into computer games. The first one is to design games that are inherently designed and implemented with the purpose of not relying on visual feedback. That is games whose

complement, as to no overload the user with haptic signals (Yuan, 2008).

playability is completely subject to interaction based on audio or haptic clues.

high definition vibration effects provided by their platform (Immersion, 2011).

Yin Wong, 2010).

**6. Haptics and games for the visually impaired** 

accessibility to games for the visually impaired.

A survey of strategies for making games accessible to the blind shows that audio is the most common used channel to either complement or substitute the visual channel (Yuan et al. 2010). AudioGames.net is an online community portal that has a repository of games whose interface is solely based on audio and the natural haptic interface of keyboard and mouse buttons (Audiogames, 2011). In terms of pure haptic games there are examples such as Haptic Sudoku for the blind, developed by Gutschmidt and others. In this technological solution they emulate visual perception completely by haptic perception. Players can feel the Sudoku board and scan the numbers by sense of touch using a haptic display, while audio cues alert the user of the outcome of their actions (Gutschmidt et al. 2010). Another example is Finger Dance, a sound based game for blind people. In FingerDance, user try to match musical rhythm patters to keystrokes in the keyboard. The game has no visual feedback at all (Miller et al. 2007).

The second approach is sensory substitution. In this case the cues that would normally come from the visual channel are replaced by haptic stimuli. This allows for the modification of currently existing games that were originally designed for non disabled individuals and adapted to be played by the blind.

Blind Hero is a typical example of a game where sensory substitution has been applied to a very well known video game (Guitar Hero from Red Octane). Guitar Hero is a rhythm action game that is played by using a guitar shaped input device with colored buttons on it that must be pressed following the corresponding visual cues that appear on the screen at the peace of some rock tune. In the modified version, Yuan and Fomer replaced the visual cues with haptic stimuli coming from a haptic glove that has small pager motors that stimulate the tip of each finger (Yuan and Fomer, 2008).

VI-Tennis and VI-Bowling are another example of sensory substitution from their analogous version of the Wii Console (Wii Sports, 2011). In this case the haptic interface is based on a motion sensing controller enhanced with vibrotactile and audio cues that allows the players detect the key events in game play. In the case of VI-Tennis the controller would provide vibrotactile feedback to reflect the event of the ball bouncing and the timeframe at which the ball should be hit in return, while audio cues were left the same they ware on the original Wii Tennis game (Morelli et al., 2010a). For the VI-Bowling they implemented a technique called Tactile Dowsing where the Wii Remote is used to sense the direction to where the bowling ball should be thrown. With the Tactile Dowsing the player moves the remote left and right in a horizontal pattern. The receiver will detect the motion of the remote and the software prompts a vibrotactile feedback on the remote in a pulsing pattern. The delay between vibrotactile pulses is regulated so that the closer the player points to the optimal direction of the throw, the lower the delay and vice versa. This way the player can sense the direction the same way by trying to position the remote in a direction that has a near continuous vibrotactile feedback (Morelli et al., 2010b).
