The Vibra API on Symbian smartphones has enabled developers to add ‘feel’ to applications for some time. However, a new generation of haptic feedback is being brought to the Symbian ecosystem by Immersion Corporation. This article explores the possibilities that may be offered by Immersion’s API and tools.

Immersion is one of the key creators of haptic technology, those little buzzes users of S60 5th Edition devices experience to make them aware of UI interactions. The company develops technology for a wide variety of applications, from high-end virtual reality simulators — to help train surgeons — through to haptic feedback for consumer electronic devices. The consumer aspect of Immersion's business is more diverse than you might imagine. It including casino slot machines and automotive applications in addition to the more usual consumer electronics such as games consoles, portable music players, and mobile phones. 

Dennis Sheehan, VP Touch Line of Business at Immersion Corporation, describes the company’s goal as “to provide tactile feedback from a touch screen that mimics, as closely as possible, the sensation a user would have experienced pressing a button. It’s all about improving the way we humans interact with technology.” As electronic devices move from button interaction to virtual controls on a touch screen, Dennis believes we are “literally losing the sense of touch feedback.”

Immersion’s technology is a combination of software and hardware. Software controls the vibrator motor or actuator in a device, while hardware partners provide the actuators and driving electronics. “Our hardware partnerships are an essential part of our technology,” says Dennis. “For example, to provide a vibration that feels like a button click we need to overdrive the vibrator motor to get sharp acceleration and then reverse the voltage polarity to achieve rapid deceleration. This places particular demands on the semiconductor controllers and the motors. So we work with the various vendors to specify their products optimally for our technology.” These partnerships mean that there is a high degree of consistency across devices in playing TouchSense feedback, Immersion’s brand for these haptic feedback vibrations. Even so, Dennis notes there is always a degree of tuning undertaken when the Immersion engine is ported to a new device or platform.

While the primary focus of the technology is to provide tactile feedback to user interface controls, it can also be used anywhere within an application where haptic feedback can enhance the user experience. For example, the technology could be used to add a rumble effect to accompany an explosion in a game. One of the oldest applications for the technology is in the games consol market, where it drives the rumble feedback in the control pads for Microsoft Xbox and Sony PlayStation. 

"You can think of the technology as analogous to an audio engine with an API that enables developers to send commands that result in sound being created,” says Dennis. “With our technology developers get a similar capability, either to play predefined TouchSense feedback or control the TouchSense engine on the fly.”



Creating a TouchSense feedback file using the studio tool in the TouchSense SDK.

The TouchSense API is not yet open on Symbian devices, but this should change with Immersion joining the Symbian Foundation. “Joining the Symbian Foundation was a natural extension of our existing engagement with Nokia,” says Dennis. Nokia is a licensee and the technology is incorporated into S60 5th Edition. “We have always provided an open API for developers to take advantage of the TouchSense Player. Joining the foundation will enable us to make the API available to Symbian developers, whether they be creating devices or applications that take advantage of the player,” says Dennis. “We are also pleased to be one of the first new component technology providers to integrate our technology into the platform.”

Dennis makes it clear that this does not mean Immersion is open sourcing their technology, but rather making it available as a pre-integrated, proven option to device manufacturers. When a device manufacturer chooses to use Immersion’s technology they are free to make the TouchSense APIs available to developers.

While the technology is currently used to provide UI interaction feedback, the API allows developers to add haptic feedback to any application. Some devices already use the API to allow users to create their own TouchSense files and assign them to contacts, so in addition to a personalised ringtone contacts can have a personalised vibration alert. Dennis also highlighted a dice game available for some Samsung phones that uses haptic feedback to simulate the feel of dice being shaken in a cup.

While the ability to add custom haptic feedback to an application may have a lot of appeal, additional power consumption could obviate the benefits. However, Dennis believes the impact on overall battery life should be minimal.

“Developers should not be saturating their applications with haptic effects,” says Dennis. “Feedback needs to enhance the user experience and overuse certainly won’t achieve that. Provide too much feedback and the user will probably turn the feature off. Take a racing game. You could add haptics to mimic the feel of an engine’s revs, but doing this could desensitise the user to more specific haptic feedback. It would be better to use feedback to highlight significant events, for example, to indicate a car had left a race track and was running on gravel.” As part of its developer program, Immersion provides guidance on adding an appropriate level of feedback.

The fact that haptic feedback is best if intermittent reduces the likely demands on a device’s battery. “Even where there is intense feedback the impact on power consumption is small,” says Dennis. Immersion has undertaken extensive modelling of feedback use and this suggests the most extreme case of normal use is typing. “Even if someone manages to type at 50 words a minute the impact on battery life is negligible,” says Dennis. “In this situation the haptic effects may add one or two percent to the power consumption. Most tasks with intense haptic feedback happen when the screen is on, and the screen has a far more significant effect on power consumption.” Dennis also points out that compared to using the standard vibration APIs, Immersion's technology is significantly more power efficient. “A typical native vibration API results in the motor starting up and shutting down slowly. This means the vibrator has to be run for a significant period of time, tens of milli seconds, to have enough force behind it to achieve the desired effect,” says Dennis. “Our technology is designed to accelerate and brake the motor much faster and therefore uses much less power."

While Immersions technology offers interesting possibilities for third-party developers, it’s not yet accessible on Symbian OS devices. However, Dennis indicated that Immersion expect the API to appear on Symbian based devices in the future. In the meanwhile, developers can explore the technology and familiarise themselves with the API and tools through Immersion’s TouchSense Mobile Developer program.