Laser pen inputs to PDAs

VPen wireless devices will use a laser instead of ink so users can input data to handhelds by writing. The first products are due by the end of the year and have some big-name backers

Israeli firm OTM Technologies has announced its intention to launch a new type of computer peripheral this year, called the VPen. The device can function as a writing tool for capturing hand-written input or serve as a mouse replacement, and works on any reasonably flat surface.

The VPen could prove a valuable tool for mobile employees needing to input text information to phones and PDAs.

"The user can write complete sentences with VPen, unlike using a stylus on a tiny PDA screen," said OTM president and co-founder Gilad Lederer. Demonstrating a prototype of the device, he quickly entered phone numbers wirelessly into a Bluetooth-enabled mobile phone by "writing" the digits across the surface of a desk.

Lederer added that the VPen would work just as effectively on a user's lap, or even the palm of a hand.

The demonstration phone was a standard model, Lederer said, but had handwriting-recognition code installed in order to process input from the VPen. However, he pointed out that this type of software nowadays comes free with most computers: "Every Windows platform now has some form of handwriting-recognition built-in." Users therefore have only to feed input from the VPen.

OTM takes its name from optical translation measurement, which is the patented technology behind the VPen. The company will not sell any end-user products itself, but is licensing its technology to partners such as Motorola, Siemens, Nokia and Microsoft. The first products are expected to ship by the end of this year.

The VPen is built around a tiny laser-based optical sensor. "It's basically just a laser diode," said Lederer. But because it is low-powered it is safe - even if the laser is pointed directly into the eye. When the VPen is held in close proximity to a surface and moved around as if writing, a small array of sensors uses the Doppler effect - changes in frequency caused by relative motion - to sense the pen's position.

"No one seems to have thought of using the Doppler effect this way before," said Lederer. "It is used in speed cameras, for objects that are travelling towards or away from a sensor, but we're using it to measure lateral motion."

The demo VPen was about 15cm in length and quite chunky, but Lederer indicated that shipping versions would be smaller. "We were worried about power consumption," he said, "so we made the pen big enough to take an AA battery. But we've found that it lasts for weeks." Production units will probably use smaller batteries and be closer in dimension to standard pens, according to Lederer.

OTM hopes that VPen devices will be a compelling application for the Bluetooth wireless interface, which is now starting to appear in many phones, PDAs and notebook PCs. Lederer argued, "People who see the VPen working say, 'now I understand what Bluetooth is all about'."

The VPen technology can be put to other uses. Lederer showed a prototype phone that worked with an optical sensor instead of the usual thumb-operated navigation key. The solid-state sensor would last much longer than standard controls, Lederer said, adding that it could also be used as the pointer device for notebooks or to create new optical mouse products. "This is much more reliable, and simpler, than the current optical mouse technology."

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