There’s a way to harvest energy from radio waves

The chairman and CEO of Drayson Technologies demonstrated the technology at London’s Royal Institution, first by using it to power a loudspeaker, and then by unveiling the first device to be powered entirely by Freevolt, its handheld air pollution monitor, the CleanSpace Tag.

Freevolt could help smooth the way to a future in which computing brains are infused into everything from tea kettles and cats to trash cans and cars.

We’re not talking about very much power – the dream of a self charging mobile phone that never needs plugging in will remain just that, unfortunately – but it’s there if you know how to get at it. And even the few microwatts that Freevolt typically delivers is about as close to being a free lunch as the uncompromising First Law of Thermodynamics will allow.

Radio isn’t the only energy source for energy harvesting.

Although it is possible that the companies who broadcast the radio waves may have something to say about the technology, and even may want paying for the energy, Drayson insists that there is no legal standing for them to claim anything.

‘But it is hard, because there is only a small amount of energy to harvest and achieving the right level of rectifying efficiency has been the issue – up until now. The company has built an efficient version of a component called a rectifier that turns the energy into a current. About 29,000 people die each year in the United Kingdom because of poor air quality each year.

Other applications for the Freevolt technology could include low-energy wearables (such as fitness-tracking wristbands) or location-sensing beacons used in shops. Data is tracked via a phone app. Changing the batteries on a tiny device like this would be a headache, which is where the Freevolt comes in, pulling enough power from the ambient RF energy to trickle power into the battery forever. The device has a lifespan of three to five years, but this is only limited by the sensor, not by Freevolt itself.

Eventually, the technology could lead to networks of devices and sensors that send data by reflecting existing signals to exchange information, without the need for batteries.

Similarly, the modules could be made larger to power multiple connected objects within a smart home. They can actually be transformed into energy, which is the subject of many research projects, like the one from the Ohio State University.