The Laws of Thermodynamics remain in force, and there still ain’t no such thing as a free lunch (TANSTAAFL). But Fujitsu’s recently developed sensor with Low Power Wide Area (LPWA) support may have folks wondering. What Fujitsu is billing in true W. C. Fields’ hyperbolic fashion as the “World’s Smallest Sensor” never needs a replacement battery. Note the company isn’t claiming No Battery, just no replacement. So assuming the Fujitsu’s claim is accurate, the advance addresses a primary Internet of Things (IoT) concern: how to replace power sources in the billions upon billions of sensing and signaling devices installed worldwide.
If you’re going to attach a sensor to every corn stalk, every head of cattle, every member of endangered species, and every buoy in navigation lanes, to call out just a few highlighted applications, who’s going to check and change the batteries? Will IoT battery changer be a new career path for those who lose their jobs to robots or will the answer depend on developing battery-changing droids? If the batteries last forever, or at least as long as needed, we won’t need to breed or design battery changers… although it does nothing for robot-induced industrial redundancies.
So how does a one-and-done battery-powered sensor relate to health tech? Think continuous monitoring with sensors placed, or sprayed. Don’t scoff at spraying sensors, by the way. When Dr. Robert Poor worked on low-power wireless mesh networking at design at MIT in the early 2000s, he envisioned the concept of sprayed networks. So if sensors can be distributed as widely as desired, real-time biometric sensor monitoring has the potential to allow people to age in place independently with confidence that, should something happen, their sensor-embedded home would detect and report the problem quickly.
Fujitsu’s new 82 by 24 by 6-millimeter sensors can transmit data several kilometers without replacement batteries. Fujitsu’s technology combines LPWA support with technology that not only recharges a tiny battery using sunlight but also monitors factors that enhance the transmission and match the current battery state. If a battery’s power waxes and wanes with sunlight, for example, transmissions are saved for times when the charge is at its highest state; this helps minimize the storage size requirement. If all the sensors are inside a house, the sun likely won’t reach them, and every day doesn’t have sunlight. However, a separate, ceiling-mounted light source inside the home could charge myriads of tiny batteries, itself powered by roof-top or community solar-energy storage. Fujitsu’s new class of sensors is a first step in what may become a great leap in sensor proliferation.