Tip-Tap: Battery-Free RFID Computer Input By Touching Fingertips in Different Ways

In developing the method, the researchers mapped the most comfortable areas on the index finger for people to touch with their thumb, and tested different designs for the input points, such as smooth, bumps, or magnets. Following user tests with an early “wired” prototype to benchmark performance, they tackled the problem of making it “battery-free.”

The researchers were able to make Tip-Tap battery-free by splitting the antenna of an RFID tag in two, and equipping each side with three chips to enable two-dimensions of fingertip input, the first time this had ever been done.

The new RFID tag can be integrated into a glove or attached directly on the skin as a temporary tattoo.

“We used this design in two prototype Tip-Tap devices, a glove with a range of four meters, and an on-skin tattoo,” said Vogel. “Such devices are useful for issuing simple commands when a user cannot easily hold an input device, and the usage context is a defined area — for example, factory workers, surgeons, or people exercising in a gym.

“This is the only device of its kind that we’re aware of that doesn’t require a battery or cumbersome wires to make it work.”

The study, Tip-Tap: Battery-free Discrete 2D Fingertip Input, was authored by Waterloo’s Faculty of Mathematics researchers Vogel, Omid Abari, Ju Wang, Ziyang Shan, Ningshan Ouyang and Keiko Katsuragawa, who is also a research officer at the NRC. The study was recently presented at the ACM Symposium on User Interface Software and Technology (UIST), the premier forum for innovations in human-computer interfaces.

Contacts and sources:
Matthew Grant
University of Waterloo