The first seismograph known to history was built by Zhang Heng nearly two millennia ago, in the days of the Han Dynasty. It could indicate the general direction of an earthquake's epicenter by dropping a bronze ball from one of eight bronze dragon's heads into the mouth of one of eight bronze toads waiting below. Granted, this wasn't a lot of data. The device could tell you that an earthquake had occurred, and it could provide some rather vague information about where it might have happened. It wasn't much, but it was a start. Sensors and their accompanying recording devices have been growing steadily more sophisticated ever since. In the modern world sensors are used in ways that Zhang Heng could never have imagined, recording everything from exhaust gas temperatures to the electrical activity in a human heart. And they don't just collect data anymore. They're becoming intelligent. Embedded microcontrollers and built-in software are turning them into thinking, communicating, and active nodes of intelligent networks, systems that demand localized intelligence and real time, sensor-driven analytics. You don't just connect them anymore; they communicate with you.
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