We already know that the sensor web is set to grow exponentially in size. For years, the Internet consisted of servers and PCs, but over the past couple of years, we have seen an explosion in the volume of non-PC devices. Tablets and smart phones are only the beginning. We can expect to see a vast panoply of Internet-connected devices, embedded in everything from cars through to buildings.
These sensors will be able to tell us new things about the environment that we live in. Cars could tell us about the temperature around them, for example while buildings could feedback on everything from background radiation to air pollution.
But how will all these devices be powered? Research into harvesting energy in tiny amounts is creating new insights into how the sensor web might be able to function autonomously for tens of years without any extraneous input.
Kinetic energy harvesting relies heavily on piezoelectric power, in which particular ceramic compounds create tiny amounts of energy when compressed. When you press a button that directly creates a spark to ignite your gas oven, or when you press a firelight and hear that familiar snapping sound before the flame appears, you are using piezoelectrics.
Researchers in micro-kinetic energy harvesting have already created small devices that vibrate a tiny amount in response to energy. These vibrations then create tiny amounts of electric energy that can be used to generate minimal amounts of power.
Recently, researchers at the University of Michigan created a device that can produce 5 to 10 times the power output than previous devices of the same size. Designed to be affixed to factory machines, which vibrate heavily, they can be used to power sensors that constantly monitor machine performance and keep production moving. The power generated could be enough to not only keep a sensor running, but also to power an efficient wireless connection that can then be used to beam data back to a central point. Other applications could include heat sensors for motor vehicles.
Talking of heat, researchers from the University of Wisconsin Madison are looking at systems that use tiny microdroplets located inside a shoe. The interaction of thousands of these droplets with a nano structured substrate turns the mechanical energy produced by walking into approximately 20W of power. This is more than enough to power a tablet device or smart phone. The company envisages a harvester-powered cellular device inside a heel that could be used for long-range communications.
Personal kinetic power generation systems aside, these tiny energy harvesting systems could make the sensors largely autonomous, which is a key challenge in scaling up the Internet of Things. We have the miniaturization capability, and the ability to produce in volume. The applications are as broad as the Internet of Things itself. Another company called MicroGen, spun out of research at the University of Vermont, hopes to put its tiny piezoelectric energy harvesting chips into batteries for tire pressure sensors. The US requires such sensors in new cars because optimising tire pressure saves fuel.
So do you think that the Internet of things will be powered by the environment that it monitors, or will piezo power be another energy revolution that fails to get off the ground?
I've been writing about technology for nearly 20 years, including editing industry magazines Connect and Communications International. In 2002 I co-founded Futurity Media with Anthony Plewes. My focus in Futurity Media is in emerging technologies, social media and future gazing. As a graduate of philosophy & science, I have studied futurology & foresight to the post-grad level.