

Sebastian Anthony

Sebastian Anthony

Sebastian Anthony

Sebastian Anthony

Sebastian Anthony

Sebastian Anthony

LONDON—Lord Drayson (i.e. Paul Drayson), the UK's former Minister of Science, CEO of Drayson Technologies, and head of the Drayson Racing team, this morning unveiled a rather wondrous new technology: Freevolt. Freevolt harvests free volts (!) from a wide variety of RF radiation sources, which can then be used to power the various sensors and microcontrollers that make up the (are we there yet?) Internet of Things.

In simple terms, Freevolt harvests ambient RF energy from high-power broadcast (DTV) and mobile network (Wi-Fi, GSM, LTE) signals. The harvester itself consists of an antenna, rectifier, and power management module—and then attached to that you might have a sensor, a microcontroller, a small amount of memory, and some means of communicating with a nearby device (a Bluetooth 4.0 radio, for example).

Freevolt is billed as providing free, "perpetual power" from "unused energy that is in the air around us." That is technically true, though the amount of power that can be harvested from ambient RF radiation is very small. According to a white paper published by Drayson Technologies, the highest ambient power densities recorded in outdoor areas around London were in the microwatts-per-square-centimetre range, where GSM, 3G, and 4G signals are strongest, with "significantly lower" power densities found inside offices, where Wi-Fi is the main source of RF.

Overall, the white paper says that the "average RF density measured in an office or external environment ranges from 20 to 35nW/cm2." After you've factored in losses from the rectifier and elsewhere in the system, usable power is probably less than half that figure. You can get more power by increasing the size of the antenna (Lord Drayson said they had looked at embedding huge energy harvesters in the walls of buildings), but for most consumer-oriented devices (sensors, smart home dongles, etc.) there won't be more than a few hundred nanowatts available.

At the unveiling today, Lord Drayson showed a Freevolt unit that simply lit up a blue LED every time it had harvested enough power to do so. At the start of the event, he asked us all to put our devices in Airplane Mode; later, after he'd asked us to turn our devices back on, the blue LED was pulsating much more quickly. (Still, it's worth noting that an LED requires a really small amount of power to turn on.)

Other researchers have attempted to do RF harvesting before, but as far as we're aware this is the first commercialisation of RF harvesting tech. Drayson said that the main, novel advances behind Freevolt are an antenna that can capture power from a range of different frequencies, and a highly efficient rectifier and power management system. Specific technical details weren't provided, however.

We asked Lord Drayson if there were any limits on the number of Freevolt harvesters in a given area, or if there was a critical number of harvesters that would then impact cellular or Wi-Fi signal reception. He said "no" in both cases.

While Freevolt isn't the magic bullet that will finally let smartphones last forever, a few hundred nanowatts is still enough power for some interesting applications. The most obvious is sensors—in fridges, rubbish bins, parking spots, traffic lights—that then feed into automation and big data-style systems. More intriguingly, you might use Freevolt tech to trickle-charge a low-powered wearable device: your Fitbit's battery might last seven days right now, but with Freevolt that might be bumped up to 10 days or more. Likewise, Freevolt might be a good solution for "smarter watches" that integrate Bluetooth, e-ink displays, and other smart'ish features with mechanical underpinnings.

Commercially, Drayson Technologies seems to be following two paths. For big partners, they will licence out the Freevolt tech, and make parts/standard designs available where needed. There will also be a Freevolt developer kit, which is primarily aimed at getting hardware hackers and other DIY types involved. There's no pricing or availability for the developer kit yet (we've asked for confirmation), but Drayson is ready for commercial partners today.

At the event today—which, rather fittingly, was in the Faraday Theatre at the Royal Institution—Lord Drayson also unveiled the first device that will make use of Freevolt technology: the CleanSpace Tag. The CleanSpace Tag has a carbon monoxide sensor, perpetually powered by Freevolt, which sends air-quality readings to the CleanSpace app on your smartphone. The CleanSpace Tag unfortunately isn't cheap: it'll cost about £55 when it launches this November through a crowdfunding website.

Drayson remarked that London has the best air-quality monitoring system in Europe, "with just 110 sensors." He hopes that with CleanSpace we can gather a lot more data about London's air quality, and importantly, air quality data from where it really matters: near people. The end goal is to hopefully accelerate important civic conversations around dirty diesel buses, Volkswagens, and other egregious pollutants. "Putting the power of information into people's hands is really quite important," Drayson concluded.