by Philippe Kahn
We look around, everything is in motion. When motion slows, life pauses. Motion shapes our lives and gravity defines motion. We want to use gestures to control mobile devices: ShakeShake® to roll virtual dice in the iPhone®, TapTap® to adjust the volume on the headset, Tilt 'n Roll™ to navigate Google maps. We use motion to control our favorite devices and interpret motion to improve our sports performance and our health.
Gravity, Galileo, Newton and Us
Gravity keeps us grounded. It's our blessing and our curse. Gravity is the key force that shaped evolution. Accelerometers sense gravity, giving us the signals to understand motion. The ancient Greeks with all their brilliance didn't understand motion, gravity or time very well. More than fifteen hundred years later, Galileo became the father of modern science. Before Galileo, with the prevalence of "Greek Cosmology," heavier things fell faster and the earth was at the center of the universe. Galileo changed everything. He was skeptical of all the grand Greek schemes. He simply used his pulse to measure time and rolled balls of different weights on the same inclines. He carefully marked where each ball came to rest with every heartbeat (about one per second). Careful observation showed that no matter what the weight was, the balls all moved following the same patterns: one unit in one heartbeat, four in two, nine in three and sixteen in four. Galileo created a repeatable and reliable experiment. Later he used water-clocks and pendulums to measure time more accurately. The Greeks were toast and the modern scientific method was invented: observe, reason and experiment. It was the dawn of the 17th century, some three hundred years ago. Newton then took all the pieces, trusted in Galileo's principle of inertia and postulated that there had to be a force that attracted the Earth to the Sun and the Sun to the Earth and everything to everything else in the universe. We still don't understand the nature of that force. But we know that gravity is everywhere, keeping the universe in balance.
Walking: Defying Gravity
Walking is so natural to humans that we forget the millions of years of evolution that allowed us to defy gravity by standing up and running on our hind legs consistently. Something that most children learn to do before they are two years old essentially defines us as a species. Our head, brain, intellect above all. Standing tall, making weapons, hunting in groups, using tools, and inventing technology has given us humans complete control of the planet. For the better and the worse. Consider this factoid: for every wild 'protected endangered gorgeous wild wolf,' there are more than 1000 pet dogs. The domesticated Canis Lupis seems to have prospered much better than the wolf in the wild. Smart move. We now get to use technology to try to better understand motion. After defying gravity, we get to measure gravity. And for this we use motion sensors. With smaller, more accurate and more power efficient sensors we can embed motion sensing in almost every mobile device. Now we are measuring and interpreting gravity and taking action.
Measuring Gravity with Sensors and Calibrating Human Motion
Thanks to Newton and Galileo, we know that we can understand motion by measuring acceleration. Kinematics, the science that studies motion, uses high-school calculus to relate acceleration, speed and position. In a mobile device, when we do this in real time we don't really integrate acceleration to get speed and speed to get position. We interpret the signals of the sensors and recognize motion patterns. Just like a good speech recognition engine recognizes words captured by a microphone. We use innovative technology to interpret signals captured by nano-technology based sensors so that our mobiles tell us how fast we are running or walking for example. The science of accelerometers is profound and essential. Satellite based navigation systems are of little use when signals vanish in an urban canyon or a wooded area or when changes in position and motion are unrelated as on a treadmill. Accelerometrics is a cool new discipline. Newton and Galileo would love it.
Putting Life and Motion in Control
The Wii changed gaming consoles by moving them from the hardcore gamer community to the mainstream. My 11 year old daughter and I love to play Mario Kart with the rest of the family. Great stuff on a big screen. On mobiles, in the palm of our hands, it's a different experience. TapTap, ShakeShake, Tilt 'n Roll are naturals. Motion now controls a whole virtual mobile world. The motion-aware mobile platform is the new media. It is going to be by far the most popular platform in the world as it is just a matter of time before everyone of our billions of motion-enabled co-humans wants one. Because life is motion.