A key feature is very cheap radios, etched right into silicon. There’s one in your smartphone. But now prices are falling to around $5. As they get cheaper, it’s becoming affordable to connect more things, like sewer pipes or trash cans. At the University of California, Berkeley, researchers are even designing computers the size of a pinhead to collect data inside the brain and transmit it through the skull. The idea is that human bodies will join the network, too.