Handhelds help 'look' across walls

MIT engineers at MIT have created the prototype of a handheld device that allows users to stand on one side and track anything that moves across the wall .

This unique Wi-Vi device will let users see any person or thing moving near or away from the wall. According to Wi-Vi's engineers, it can 'catch' very small movements.

The device's author says Wi-Vi works by emitting Wi-Fi signals on a wall. Some of these signals will penetrate the wall, reflecting on the person on the other side of the wall and then returning to the device. Wi-Vi will emit two inverse signals.

If both of these signals hit a stationary object, such as an object or the wall itself, they would cancel each other. However, if they hit the subject of motion, the suppression status will not occur and the movement will be reflected on the screen of the Wi-Fi device.

When Wi-Vi detects a moving object, it will easily cling to this person and ignore all other things that are still around him. The authors also assert that their device can 'track' more than one person at the same time. In the demonstration experiment, the authors showed that the Wi-Vi can keep up with the movement of the three.

Researchers say devices such as Wi-Vi can help police officers and rescue workers find those who are hiding or who are trapped in rubble. For capturing motion, Wi-Vi can also be integrated into the lighting control system or other indoor devices with the arm movement.

The authors say they will present their invention at a conference organized by the American Computer Society. "We want to create a low-power, portable, and simple device that everyone can use ," said Dina Katabi, head of Wi-Vi.