This project involves a group of PhD students from the Computing Science Department of the University of Glasgow, Scotland. Our aim with this web site is to publicly experiment with user interface design prototypes, implemented on the Apple iPhone utilising its built-in variable intensity actuator and multi-touch screen.

Why Haptics?

Perhaps through a lack of foresight or laziness, mobile device user interface elements are based on desktop widgets not originally intended for small screen finger-based interfaces. Given the dynamic nature of mobile environments, many interaction scenarios can arise and mobile UIs should be designed to accommodate these.

The term haptic, in general, refers to the sense of touch. Mobile devices can provide users with haptic feedback. Using recent devices, this feedback can be presented via a touchscreen by applying forces, vibrations or motion to the user’s fingertip. Our various different haptic UI concepts and widgets revolve around interaction afforded by fingertip controlled interfaces with an aim to revolutionise mobile device interaction design and escape traditional desktop designs haunting our mobiles today.

The majority of interaction on a mobile device is visual thus placing a huge demand on the users visual attention which can be dangerous in certain mobile situations or socially inappropriate in meetings for example. Furthermore, when interacting with a button - for example, with the fingertip - the image of the button is covered by the fingertip and therefore any visual feedback can go unnoticed.

By using haptic feedback, users can physically ‘feel’ their interface and any feedback provided thus reducing the visual demand and allowing for more socially appropriate and subtle interaction.

Prototype 1: Haptic Keyboard

Although the keyboards used on touchscreen devices are based on the original physical mobile keyboards, one important feature is lost: the buttons cannot provide the tactile response that physical buttons do when touched or clicked. Without the tactile feedback, users can only rely on audio and visual cues which can be ineffective in mobile applications.

One of the key features lost in touchscreen interaction is the ability to feel the buttons. For instance, although touchscreen keyboards are based on physical keyboard designs, they do not produce the natural haptic response which occurs when a button is touched. There have been recent studies into the use of mobile touchscreen devices and the incorporation of virtual tactile feedback with fingertip interaction (1). It has been shown that tactile feedback can be added to button presses using standard mobile phone vibrotactile actuators and can be beneficial to mobile device users, increasing typing speeds and reducing errors.

The Click

Haptic feedback has been added to the finger down and up events triggered when a keyboard button is clicked. These events have been adapted to create a fingertip-over event which is fired when the finger moves over any button in the interface. When the fingertip-over event is triggered, a 1-beat smooth 70ms high intensity Tacton (2) is presented using the iPhone’s built-in rotational motor. The cue uses an approx. 175Hz sine wave with increasing intensity during the ramp up time and decreasing intensity during the ramp down time to create a smooth rounded feeling button.

The iPhone's built-in vibrotactile actuator is shown in the top left hand corner of the above picture. This is turned on when the keyboard buttons are pressed. We have found that the actuator can vibrate at 12 different speeds offering a wide range of tactile sensations.

When the button is released by the finger, a second 1-beat Tacton is presented to confirm that the button has been pressed successfully. This feedback is 50ms and approx. 100Hz thus producing a shorter lower intensity haptic click. By adding haptic feedback to both the finger down and finger up events during button clicks, the natural snap ratio of a physical button is reproduced virtually.

Fingertip-Over-Edge Event

Another key feature lost in a touchscreen keyboard is the ability to feel the edges of the keys. We have created a tactile equivalent to this so that users can feel around the display and know when they were on a key or moving between one key and the next.

An event is triggered whenever the fingertip moved over the edge of any button on the screen, indicating a transition or slip from one to the next (fingertip slips can be troublesome for users and can cause errors that are often undetected). This allows users to run their fingertips over the buttons feeling all of the edges.

News Coverage

TUAW: iPhone Haptic Keyboard Prototype debuts

Ars Technica: Students Add Vibrating Feedback to iPhone Keyboard

PhoneMag: iPhone haptic feedback keyboard in development

Mobile Magazine: iPhone Virtual QWERTY Keyboard About to Get Haptic

PDAStreet:Proof of Concept Applet Brings Touch Feedback to iPhone Keyboard

Gizmodo: iPhone Haptic Keyboard Prototype Introduced: Does Anyone Care?

Engadget Mobile: iphone-haptics makes typing on the iPhone just a little more lively

Future iPhone Haptic Elements

We are currently developing new haptic interaction concepts for use with the iphone which enhance interaction with lists and a completely new interaction technique solely for fingertip interfaces. Stay tuned.

Prototype 2: Haptic Lists

Prototype 3: Haptic Application Launcher

References

1. Hoggan, E, Brewster, S.A. and Johnston, J. Investigating the Effectiveness of Tactile Feedback for Mobile Touchscreens. To appear in Proceedings of ACM CHI2008 (Florence, Italy). ACM Press Addison Wesley.

2. Brown, L. M. and Brewster, S. A. Multidimensional Tactons for Non-Visual Information Display in Mobile Devices. In Proc MobileHCI 2006, ACM Press (2006), 231 - 238.

Contact Us

You can contact us by email. Our addresses are the project owner names in the top right box, and append @gmail.com

Disclaimer

Our applications use undocumented methods and as a result can be unstable, we have not damaged any iPhones ourselves but please be careful and use our software at your own risk. If the vibrations get "stuck" on, then run the application again and, on the next tap, they will stop. The long-term effects of continually using the vibration actuator in this way are not yet known, for example, battery life or vibrator failure. These should be investigated before making long-term use of this software.