Imagine knowing exactly when you need to change your baby’s diaper, without a need to check or guess. A new ‘smart diaper’ designed by a team of Japanese researchers can do just that. The diaper is powered by flexible circuits that are thinner than a piece of plastic wrap, and have been implanted in the human body to monitor temperature and blood pressure in the past. The version of the sensor used in the diapers is organic and disposable, and is printed on film using inkjet technology. The sensors look for changes in pressure, temperature and – most importantly – wetness. If any of these triggers are hit, it sends a signal to an external monitoring device. The research team believes the sensors can be produced for no more than a few cents, so it wouldn’t drastically jack up the price of diapers. And since the sensors receive their power from that external monitoring device, they’re completely safe to have next to the skin with no risk for electrical shock.