There have been several attempts made to give users Jedi-like powers to control computers and smartphones using a combination of a smartwatch and some gestures. But what if you wanted to control the smartwatch itself using a gesture? It might still be a long time coming as a commercial product, but the journey has already been started by researchers Chris Harrison and Yang Zhang from the Human Computer Interaction group at Carnegie Mellon U. Their prototype wrist strap can see inside the arm and track muscles, which can be interpreted as gestures to control a device.
The prototype is called Tomo, named after the technique used for this seemingly magic feature. Electrical Impedence Tomography is a well known method in the medical field and isn’t that much different from PET and CT scans. The key difference, however, is that Tomo’s setup is exponentially cheaper and smaller than professional medical equipment, allowing it to fit inside a strap worn over a wrist, potentially a smartwatch strap sometime in the future.
A simple EIT setup would have an emitter sending out a high-frequency AC signal captured by the receiver and the impedence of the travel of that signal can be calculated and interpreted as desired. Multiplying and multiplexing the number of emitters and receivers can practically produce a 2D impedence map of an object. Or in this case, the muscles inside the wrist. Here, the data can be interpreted as muscle contractions and expansion, which can then be mapped to different wrist, hand, and finger movements.
The work is hardly finished, as you can already tell by the way the Tomo prototype looks even when strapped to a Samsung Gear smartwatch. More than just the appearance, however, there are still a few missing puzzles let to be solved. For one, the recognition of muscle movement is almost a very personal pattern, so users would have to first train the system to recognize different gestures, which can be a chore to do when setting up a smartwatch for the first time, for example. But more importantly, the impedence readings also depend on how the emitters and receivers are positioned and how the strap is worn, which might vary from day to day or even moment to moment.
Still, it is an interesting proposition, especially given the small size and price involved. In the future, it could very well become a standard feature of smartwatches, wearables, or maybe even ordinary accessories.