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Energy harvester turns radio waves into ‘perpetual power’ for IoT devices

Thu 1 Oct 2015

Freevolt energy harvester

A new technology which holds the potential to power low-energy devices perpetually has been developed by green-conscious research firm Drayson Technologies.

The system, named Freevolt, is able to capture left-over energy from radio frequency (RF) signals and turn it into ‘perpetual power’ – creating electricity out of thin air.

There is an ever-dense mesh of RF signals bouncing around in the ether with increasing demand for smartphone data, Wi-Fi, and digital broadcasts. Harvesting energy from this resource is not a new concept, but most prototypes have required dedicated transmitters that power devices at short range.

Lord Drayson, former Labour science minister and founder of Drayson Technologies, explained that the Freevolt operates using three key parts; a multi-band antenna, which hunts out RF energy within the 0.5-5GHz range, an ‘ultra-efficient’ rectifier which transforms it into DC electricity, and a power management module that boosts, stores and outputs the electricity.

The company claims that Freevolt is the most efficient RF harvesting system, with no dedicated transmitter required. However, the amount of power harnessed by Freevolt is limited by the density of RF signals available, which are more prevalent in cities and towns than in rural areas.

Additionally, the technology can only power very low-energy devices, such as wearables and sensor-based IoT products (i.e. smart smoke alarms, security cameras, indoor mapping beacons etc.) The system would not be able to power a smartphone – even in a dense RF signal spot, Freevolt can only produce 100 microwatts of power.

Drayson’s idea extends much further however, envisioning whole smart cities run by sensor technology which never needs charging, costs nothing to run and isn’t limited to certain locations by proximity to external power sources.

In the future the former minister hopes to scale up his design for devices requiring higher power outputs, and to create miniature and flexible versions for applications such as smart clothing.


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