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This Invisible PC Mouse Only Cost $20 to Make

Three students from MIT's Media Lab have created an invisible computer mouse costing only $20 to build. Instead of the typical hands-on peripheral, the "invisible mouse" uses a line-capped infrared laser and an infrared tracking camera to interpret the user's hand movements. In turn, those movements are translated into on-screen actions such as button clicking and cursor placement.

As seen in the video below, the user acts as though a real mouse exists on the desktop, conforming his hand around its rounded shell and clicking on invisible buttons using his right index finger. The laser is mounted at the bottom of the laptop and positioned just above the user area, shooting an invisible plane. The camera is mounted on the top corner of the display, aimed down at the action area.

According to the students, movement is determined by the camera as it registers and interprets the changing field shapes. The info is then translated into mouse movement or button actions via proprietary software installed on the laptop--the right middle finger can even perform right-click commands.

"As we improve our computer vision algorithms, an extensive library of gestures could be implemented in addition to mouse movement and mouse clicks," the group said. "Typical multitouch gestures, such as zooming in and out, as well as novel gestures, such as balling one’s fist are all possible. In addition, the use of multiple laser beams would allow for recognition of a wider range of free hand motions, enabling novel gestures that the hardware mouse cannot support."