If You Could Talk To Walls - Your Body As An Antenna

If you've spent as much time talking to the wall as this writer, then you'll no doubt be just as pleased about one of the latest innovations from Microsoft Research's Computational User Experiences team. In an award-winning paper, they outline how the body acts as an antenna, and explain how it could therefore be used as an interface with the appliances in your home, thus "turning the whole home into an interaction surface."

The key is in the electromagnetic noise generated by these appliances and the power lines running through your walls and ceilings. These are impacted by our very presence, because the "human body is an electrical conductor, and thus when exposed to electromagnetic fields, it behaves as an antenna with a frequency resonance determined by various factors including height, posture, etc."

Cool, huh? And a bit of a worry, when you think about it. But definitely a valuable tool, in the right hands. And Microsoft Research are pretty handy when it comes to these things.

And a simple one, too. The team have been able to "enable new user interaction capabilities in the home that require no additional instrumentation to the environment, and only a simple analog-to-digital converter on the body itself."

Which could start you wondering why nobody ever thought of this before. But, as George Sand noted, "Simplicity is the most difficult thing to secure in this world; it is the last limit of experience and the last effort of genius."

Anyway, the team conducted experiments in 10 houses, aged between five and over 60 years-old, in which subjects stood at arm's length from a wall in front of a light switch or electrical outlet, and performed a series of gestures, while a conductive pad on the back of their necks recorded the voltage going through the body. 

Sure enough, the closer they got to the switch or outlet, the higher the voltage going through their bodies. With this simple procedure they found that they "can determine the location of the user in the home, with near 100% accuracy, and can determine whether the user is touching a wall or not with 98% accuracy."

Which has big implications. For a start, this technology can be "integrated into an interactive real-time system for gesture sensing in uninstrumented homes." You could use gestures for digital lighting, thermostat control, or to guide your home audio system. And because everybody is a unique 'antenna', everyone in a house could have their own custom gestures to keep their home constantly at their command. And then, of course, are the gaming and computing possibilities - let your imagination run wild with that one!

Here are two of the team members, Desney Tan and Dan Morris, demonstrating some of their other - closely related - work with Natural User Interfaces (NUI):