TECHNOLOGY FOR CHANGE

3D in-Air Mice Proliferating into Open Source

R. Colin Johnson | Date: 11-09-09 | Comments

OEMs can create their own 3D in-air controllers based on Freespace technology using an open-source software library called "libfreespace."

Smarter 3D in-air mice are the forte of Hillcrest Labs, which made its name in motion control technology by creating software for original equipment manufacturers (OEMs). Now the company has its own 3D controller�called the Loop�available directly to consumers, as well as open-source software for Windows, Mac OS and Linux.

The Consumer Electronics Association reports that more than 7 million U.S. households have already connected a personal computer to their home television sets. Companies like Logitech have already licensed Freespace motion control technology to create 3D in-air controllers, but now Freespace creator Hillcrest Laboratories (Rockville, Md.) has a smarter idea for TVs connected to PCs�its own specialized 3D controller called the Loop Pointer: In-Air Mouse for TV.

"We've designed the Loop pointer for the growing number of consumers who connect their PC or Mac to a TV," said Chad Lucien, vice president of Freespace Products at Hillcrest Labs. "The Loop is a unique Freespace mouse that lets users control an on-screen cursor with the flick of wrist."

The key to the Loop is its use of both a three-axis accelerometer and a three-axis gyroscope, both cast onto tiny silicon chips using micro-electro-mechanical system (MEMS) technology. Accelerometers were made famous as the triggers for automobile air bags�the first "killer" application for MEMS technology. The microscopic mechanical actuators on the accelerometer chip were the only sensing elements that were fast enough to fire an air bag in the required millisecond time frame.

Since then accelerometers have become standard equipment on consumer devices such as the iPhone, where it senses the motion of rotating the screen from portrait to landscape orientation, and the Nintendo Wii for its "nunchuk" style video game controller.

However, an accelerometer only senses motion, so Nintendo had to add infrared sensors to sense its controller's absolute location in space. Now, however, MEMS gyroscopes are taking over the function of sensing your location in space for the next-generation of smarter 3D in-air controllers.

A gyroscope uses an internal rotating reference frame to track the absolute location of a controller using the Coriolis effect. Normal-sized gyroscopes work like a rotating bicycle wheel that "wants" to stay upright, creating an opposing force to changes in position that can be sensed. Given a starting position, a gyroscope can tick off precisely how much a device has been moved and in what direction.

OEMs can now create their own 3D in-air controllers based on Hillcrest's Freespace technology using its newly announced open-source software library called "libfreespace" and its Freespace Reference Kit, which include a PC board housing the accelerometer and gyroscope MEMS chips. The new library supports the Linux, Mac OS X, Windows XP, Windows Vista and Windows 7.0 operating systems.