**4.3 Game pads**

It is the most common kind of game device that provides input in a computer game or entertainment system used to control a playable character or object. Its design was conceived to be hold in both hands with thumbs and finger used to press buttons to provide input. Thus the main goal of game controller is to govern the movement/action of payable body/objects in a video computer game. Gamepads usually feature a set of action buttons handled with the right thumb and a direction controller handled with the left. Later on some common additions to the standard pad include shoulder buttons placed along the edges of the pad.

The Role of Haptics in Games 227

mobile world. Smartphones and related devices are capable of rendering videogame graphics and sound in high definition, which aims at immersing the player in the game

Because mobile video games are inherently restricted to small screens, game developers must rely on advanced user interface design to fulfill the input/output streams of media information necessary to play the game. Furthermore, most of the portable devices that serve as a platform for modern mobile games feature a touch screen as the main way of interaction with the device and its software interface. Most of the time such devices, either completely lack or, have very few physical buttons that the player can use to play the game. Even when physical buttons are present on the device, they are often located in places where using them as part of the game input controller makes it awkward for the player. In terms of haptic feedback, this is a limitation of such devices, since touch screens lack that physicality that players have grown used to with pc and other gaming consoles and their

To help with the lack of physical buttons and the sense of touch that they provide, mobile phones and devices are often capable of reproducing a vibration feeling. By controlling the moment, and duration of the vibration, to be synchronized with the touch of the screen, such mobile devices compensate the lack of hard buttons by giving a haptic feedback to the user whenever he/she presses a soft button on the touch screen. Although this is often good enough for common in-device tasks such as entering text on a virtual keyboard, from a gaming perspective the approach is very limited, as is the hardware available in most devices. Games require a higher degree of variation on the vibration to produce more rich and realistic experiences. Different levels of intensity, duration or even a specific vibration pattern must be applied for different events in the game play. The challenge in providing such degree of high definition on the haptic feedback is twofold. On one hand, hardware on the devices must be sufficiently advanced to permit the variation of intensity at which the internal motors will cause the vibration. And on the other the software must be sufficiently sophisticated to control the motors in such a way that a wide array of vibration effects can

Research has been mostly focused in developing vibrotactile rendering techniques that can allow for a sophisticated touch feedback experience. Different algorithms have been tried to control the vibration motors and render the desired effects. Sang-Youn and others proposed a Traveling Vibrotactile Wave rendering technique which makes the effect of a traveliing sensation across the device display. It is based on controlling the vibrations of two motors, which permits to specify the location where the overlapping of two waves occurs. This control further allows the generation of a sensation of continuous flowing vibration by constantly changing the overlapping point, adjusting the timing of motor actuation. They tested their rendering technique with a ball rolling game (Sang-Youn, 2009). In another related work, they tested a miniaturized vibrotactile rendering system based on an eccentric vibration motor and a solenoid actuator, which generates vibrotactile information having a large bandwidth and amplitude. Their intention was to generate event-specific vibrotactile effects for a car racing game in a mobile device. The system could render human discernible effects for the events of

collision, driving on a bump, and driving on a hard shoulder (Sang-Youn, 2006).

A good example on the latest advances in this direction is the MOTIV platform from Immersion. Their solution provides a TouchSense embedded controller technology to

experience even with the limited size of the screen.

controllers.

be rendered.

Third generation of video game controllers included the Nintendo Entertainment System (NES) featured a brick-like design, Master System which has a similar design as NES and the Atari 7800. The fourth generation included Genesisi Mega Drive by Sega, TurboGrafx-16/PC-Engine and the Super Nintendo Entertainment System which had a more rounded dog-bone like design and added two more face buttons, "X" and "Y", arranging the four in a diamond formation.

In the Fifth Generation the Apple Bandai Pippin had a short live console designed by Apple Computer Inc. The Atari Jaguar was the first and last Atari console to employ the modern gamepad. Another example is the Neo Geo CD which was similar in shape and size to Sega Genesisi/Mega Drive game pads. Other examples include, The Sega Saturn, whose control pad introduced an analogue stick and analog triggers, Virtual Boy controller designed to use dual joypads, which was envisioned to control objects in a 3D environment. Sony developed a four direction D-pad, four actions were referred not by color or letter/number like most pads instead were colored shapes; triangle, circle, cross and square. The basic design and layout was based on that of Nintendo's SNES controller, as the PlayStation was originally developed as a CD add-on for the SNES, before becoming a console in its own right. It was the default pad for the first year of the PlayStation, until the release of the Dual Analog. It was often cloned for PC gamepads. The Nintendo 64 started to have both an analog stick and a D-pad. It has the traditional A,B,L and R buttons, along with a Z trigger button on its underside.
