Accelerometers are devices that can measure acceleration (the rate of change in velocity), but in smartphones, they're able to detect changes in orientation for example the accelerometer is what tells the screen to rotate. Basically, it allows the phone to know up from down.


Despite the accelerometer's regular use for games, videos, and other smartphone activities, few people know how the gadget actually works, or how engineers were able to cramp such a small but important piece of technology, which can detect motion in three directions, into a millimeters-thick smartphone. I plan to take this technology and use it for the app. It would not be used the entire workout but to help with measurements or to show what a movement should feel like and then the operator can try and mimic as close as possible.