Tech Digest daily roundup: Sweat used to power medical sensors


Small biofuel cells can harvest enough energy from the sweat on a person’s fingertips to power wearable medical sensors that track health and nutrition – and because our fingertips are one of the sweatiest parts of the body, the sensors could be powered all day. Lu Yin at the University of California, San Diego, and his colleagues created a device that breaks down a dissolved compound in sweat called lactate. It comprises biofuel cells that fit into thin pads that are stuck to the fingertips. They soak up sweat into a thin layer of foam, where an enzyme oxidises lactate in the sweat to create an electrical charge. Each finger pad can generate 20 to 40 microwatts of power and harvest 300 millijoules of energy per square centimetre during 10 hours of sleep. This isn’t enough to run power-hungry devices like smartwatches or mobile phones, but more than enough for lightweight sensors that detect a range of metrics such as heart rate, vitamin deficiencies and glucose levels.

Websites for a Russian-linked ransomware gang blamed for attacks on hundreds of businesses worldwide have gone offline. Monitors say a payment website and a blog run by the REvil group became suddenly unreachable on Tuesday. The reason behind the disappearance is unknown, but has sparked speculation that the group may have been targeted deliberately by authorities. It comes amid growing pressure between the US and Russia over cyber-crime. US President Joe Biden said he raised the issue with Vladimir Putin during a phone call on Friday, after discussing the subject during a summit with the Russian president in Geneva last month. BBC

The iPhone 12 range has excellent cameras, but what it doesn’t have is long-range photography, unlike, say, the Samsung Galaxy S21 Ultra, which offers 10x optical zoom. That’s because no current iPhone has a periscope camera, but it looks very likely that a future one will, as Apple has just been granted a patent for a periscope system. Spotted by Patently Apple, the patent dubbed ‘Folded camera’ was filed with the USPTO and describes a system that allows the light entering the camera to be reflected at an angle, so the lenses can be laid out horizontally within the phone, rather than being stacked vertically. This allows for longer range zoom without having the camera stick way out of the back, which would be required for a conventional telephoto lens that offers 5x or 10x zoom. Tech Radar 

Apple has quietly released a new magnet-powered battery pack – that awakes a previously hidden feature in the iPhone. The battery pack makes use of Apple’s new MagSafe technology to snap onto the back of newer iPhones, and provide them with charge. It follows a range of other MagSafe accessories made by Apple, which include cards and leather wallets for cards, as well as charging pucks to plug into the wall. It costs £99, or $99, and can be ordered from Apple now. It comes in only one colour – a soft white similar to the colour of Apple’s charging bricks – and is shaped like a rounded rectangle. Independent 

The 5G rollout across Britain is being held up by owners of phone mast sites who are refusing to accept swingeing rent cuts. Fox Lane Sports and Social Club in Leyland, Lancashire, is one of the landlords being offered around 10% of the current rent it receives and has responded by refusing to allow mast operator EE to install 5G equipment. Club committee member David Bradshaw said the proposed reduction, from £7,400 a year to £700, is unacceptable. “When they say £700 we’d rather not have it, we might as well do [deals] with other sponsors who come on site and enjoy better partnerships,” he said. “What we’ve found in the last few months is that there are many more people, churches and schools and so on, that are in the same position as we are.” Sky News

Chris Price
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