5G phone networks could provide power as well as communications

THE IDEA behind the Internet of Things (IoT) is that the world would be a better place if all sorts of objects that are not currently computerised were to become so. Microchipped bridges could report when they needed maintenance. Billions of tiny computers affixed to buildings could monitor air quality and traffic patterns. Scattered across fields, such computers could analyse nutrients and water in the soil. Arm, a Britain-based designer of the sort of low-power chips the IoT will need, reckons there could be a trillion connected gizmos in the world by 2035—more than 100 for every person on the planet.That raises the question of how to power them. Regularly replacing a trillion batteries would be inconvenient, to say the least. Researchers have built chips that scavenge energy from light, heat or vibration. But such sources produce only a trickle of power, and are usually used to supplement a battery rather than to replace it.