You’re probably not aware of it, but the air around you is a dense cloud of radio frequency signals. And you’d rather be happy about that: they provide your mobile phone with 3G, your laptop with wifi and your TV with digital broadcast. Without going into details –let’s leave that for a physics class — the signals are electromagnetic waves that carry energy from a sending antenna to a receiver. Imagine you could tap of a little bit of the energy of all the waves bouncing around. That’s exactly what Freevolt does.
According to developer Drayson, Freevolt is the first commercially available technology that extracts energy from the ambient radiosignals. It’s extremely efficient thanks to its simplicity: it consists of only three parts, being an antenna to pick up the power out of the air, a rectifier to turn the alternating current into direct current and a power management module to store and ouptut the electricity.
A demo of the Freevolt technology, powering a small speaker (photo: Sebastian Anthony)
You are probably wondering how much energy this neat little device could harvest from the surrounding air. I’ll tell you: around 100 microWatts. That may sound little –it actually is, it would take ages to charge your smartphone with it– yet it is sufficient to power small devices such as smoke detectors, small security camera’s, sensors in fridges, parking lots… basically all small devices that could be part of the internet of things.
Imagine you would never have to worry about charging these devices or changing batteries. Freevolt branded it Perpetual Power for a reason. Yet as an engineer I want to get rid of some misunderstandings here. This technology is freewheeling on existing waves boucing around and since in the future we rather will have more than less of them, it may sound like an infinite power source. Too bad there’s the first law of thermodynamics, which tells us that energy cannot be created (nor destroyed). The Freevolt technology is doing nothing more than extracting some energy from the waves, energy that was invested by the sender to emit the wave in the first place.
A developers kit is available for the geeks to play around with the technology. Dryson also developed the Tag, a small sensor that keeps track of the air pollution around you and gathers the data on an the Cleanspace app on your mobile device. It rewards you when helping to improve the air quality, like leaving the car and taking the bike instead. It’s a nice showcase for their technology and hopes to build awareness on air pollution at the same time.