The Apple Watch and Microsoft Band use optical sensors to measure heart rate. The Jawbone Up3, which instead tracks your resting heart rate, uses bioimpedance sensors and several electrodes to measure your skin’s resistance to a small amount of electrical current. Originally, all photography was monochrome, or black-and-white. Even after color film was readily available, black-and-white photography continued to dominate […]

This is a user-defined post excerpt. It should be displayed in place of the post content in archive-index pages.