It’s simple enough to place an always-on camera; somewhere it can have solar power or the grid; but deep in nature, underground, or in other unique incidents every drop of energy is valuable. Fortunately, a new kind of mini-sensor for DARPA applies none at all until the thing it’s built to identify results to show up. That means it can remain for years without so much as a battery top-up.
The concept is that you could install a few of these things in; say, the miles of tunnels beneath a decommissioned nuclear power plant or a mining system; but not have to put wire around them all for electricity. But as soon as something pops-up; it’s recognized and communicated immediately. The power specifications would have to be almost naught; obviously, this is the reason why DARPA called the program Near Zero Power RF and Sensor Operation.
Moreover, this mini-sensor is built to recognize infrared light waves; unseen to our eyes but still sufficient from heat sources; such as cars, fires, people, etc. But as long as none are available, it remains powered off.
But when a ray does rise, it hits a surface is covered in tiny patches that amplify its effect. Plasmons are a sort of peculiar behavior of conducting material; which in this case react to the IR waves by blazing up.
“The energy from the IR source heats the sensing elements; which, in turn, cause physical movement of key sensor components,” wrote DARPA’s program manager, Troy Olsson, in a blog post. “These motions result in the mechanical closing of otherwise open circuit elements; thereby leading to signals that the target IR signature has been detected.”
Take it like a propeller in a well. It can lie there for years without doing anything; but as soon as somebody drops a stone into the well; it hits the propeller, which rotates and turns a lever and stretches a string. This causes a flag to be raised at the well owner’s house. Besides, as Olsson further illustrates, it’s a little more refined.
“The technology features multiple sensing elements—each tuned to absorb a specific IR wavelength,” he wrote. “Together, these combine into complex logic circuits capable of analyzing IR spectrums; which opens the way for these sensors to not only detect IR energy in the environment; but to specify if that energy derives from a fire, vehicle, person or some other IR source.”
The tech of the mini-sensor is detailed in a paper issued today in Nature Nanotechnology.