The idea is that every parcel in a post office would transmit its position, origin and destination so that it can be tracked and routed more efficiently, that every product on a supermarket shelf would transmit its contents, price, shelf life and so on, that your smartphone would interrogate the contents of your fridge and cupboards every time you walk into the kitchen to warn you when the milk is running low. And so on.
Each of these things will enhance our businesses and lifestyles in a small way. But taken together, this Internet of Things will entirely transform the way we interact with the world around us. That’s the hope at least.
But there’s a problem: these tiny identifying devices require a power source. Batteries are expensive and impractical so computer scientists are hoping to harvest the necessary energy from the environment, in particular from lights and from human motion.
The question is how much energy is available in this way. That’s relatively straightforward to answer for indoor lights (about 50-100 microwatts per cm^2). But the energy available from human motion is much harder to assess.
More info here.