Unfortunately the paper didn’t include source code so [Daniel] created his own implementation of Doppler gesture sensing in JavaScript ... spectrum of the signal. As you move your hand closer ...

For example, in my kitchen, my iPhone 4 previously displayed five full bars, and now only displays three. However, in lower-signal areas (such as my upstairs bathroom or my desk in the office ...

“For example,” Apple wrote in its letter, “we sometimes display 4 bars when we should be displaying as few as 2 bars.” This update also brings some minor changes to the signal bars ...