



Video: See how an old cellphone can become smarter

The latest touchscreen? (Image: Niall Macpherson/iStock)

Embarrassed by your “ancient” push-button cellphone? Touchscreen envy eating you up inside? Fear not. New software could offer users of cheaper push-button phones access to some of the features usually found only on the more pricey smartphones.

Called TouchDevice, the program renders the entire casing and LCD display of a standard phone sensitive to touch – or, rather, the sounds of touch. And it needs no new hardware, so can be applied to most existing phones, its creators claim.


The TouchDevice software, developed by Input Dynamics of Cambridge, UK, will let users scroll through menus, browse or zoom; all by swiping, tapping or scratching a fingertip, touchscreen-style, along the side of the phone.

Instead of selecting onscreen icons with a joypad, they can tap the icons as if the traditional display was an iPhone-style capacitive touchscreen. Tapping the phone casing a number of times activates pre-selected functions like the address book, texting service or camera.

Telltale taps

So how does it do work? Through smart use of the phone’s built-in microphone, says inventor Giovanni Bisutti. Every tap on the phone’s screen or its casing produces a telltale sound that resonates through the device. Careful analysis of the sound patterns can identify where and how the phone was touched.

“The built-in mic picks up these ‘acoustic fingerprints’ and the TouchDevice software algorithms work out which spot on the phone was tapped or swiped,” says Bisutti. For every make of “dumbphone” that TouchDevice runs on, the algorithms must be trained to recognise the device’s acoustic properties, but he says it’s easy to do and won’t add significantly to the costs.

The software can identify the point of contact to within about 1 square centimetre. At the Meerkats and Avatars conference in Cambridge, UK, today the firm demonstrated a version able to identify single crisp taps from a finger nail or stylus. The firm says that it is refining its algorithms to interpret the acoustically distinct signatures made by scratching the device with a fingernail, tapping it with a softer finger tip, and swiping the device with a finger. In future they say that the algorithms will be able to handle taps from multiple finger tips at once, turning old phones into multi-touch devices.

Nail-biting challenge

As yet, no phone-maker is building the software into its entry-level phones. However, Bisutti says he is in talks with “tier-one handset manufacturers, the big ones” about licensing the software. “They see the advantages. It lets them build a touchscreen phone without the need for expensive hardware – and the software can be uploaded into existing phone designs,” he says.

Commentators like the idea. “If it works it sounds like a neat way to expand fairly limited devices,” says Peter Bentley, a software engineer at University College London and author of an acoustics-based iPhone app, iStethoscope, which recently topped Apple’s App Store charts. “But I wonder how it will cope with people who bite their fingernails as that will change the acoustics.”

The notion of acoustic fingerprinting hit the headlines earlier this year when Chris Harrison at Carnegie Mellon University in Pittsburgh, Pennsylvania, developed a human-skin-based cellphone control system called Skinput. Skinput uses compact projectors, dubbed picoprojectors, to turn skin into a ‘touchscreen’ that, for instance, allowed people to tap an icon projected on their forearm to answer a call. The tap’s acoustic signature – a resonant ricochet through the arm’s bone, muscle and fat – activated the phone’s answering mechanism.

“Acoustics fingerprinting is really neat in that you can turn a totally passive item like a table or, in this case, a cellphone, into an interactive surface,” says Harrison.