The technology industry is tapping into the growing market of people who want to chart their daily lives in excruciating detail.
That means gadgets and mobile applications able to measure everything from calories burned to how often a baby eats, sleeps or needs a fresh diaper.
Tim Davis of Beaver, Pennsylvania, says he used some 15 devices to track every aspect of his health. A scale tweeted out his weight and an app tracked his moods.
Davis says the technology inspired him to lose more than 60 pounds (27 kilograms), though he gained much of it back as soon as he stopped tracking his daily habits.
Researchers are taking notice of people such as Davis _ and whether self-tracking devices could be used to improve public health or the environment.