Tech
Solid-state device harvests body heat to power battery-free wearables and IoT sensors
A research team affiliated with UNIST has unveiled a technological advancement that allows body heat to generate electricity sufficient to power electronic devices. This innovation paves the way for the commercialization of battery-free wearable gadgets and Internet of Things (IoT) sensors that operate solely on heat generated by the human body.
Led by Professor Sung-Yeon Jang from the School of Energy and Chemical Engineering at UNIST, the research team developed the world’s first high-performance n-type solid-state thermogalvanic cell capable of powering actual electronic devices. The paper is published in the journal Energy & Environmental Science.
Thermogalvanic cells are compact generators that convert temperature differences—such as the human body temperature (~36°C) versus surrounding air (20–25°C)—into electrical energy. However, due to the minimal temperature gradient, previous systems struggled to produce enough power to operate real-world electronics.
The newly developed solid-state device overcomes this challenge by delivering sufficient voltage and current to power practical devices. While solid-state designs typically offer advantages such as safety from leakage, ion mobility issues within the electrolyte have historically limited their current output. The research team engineered an electrolyte that facilitates efficient ion transport, and further, the thermally driven ion diffusion enhances overall output voltage.
By connecting 100 of these cells in series—similar to building with LEGO blocks—approximately 1.5V can be generated from body heat, comparable to standard AA batteries. Connecting 16 such series-connected modules enables the activation of devices like LED lights, electronic clocks, and temperature/humidity sensors.
Notably, the cell’s Seebeck coefficient (voltage change per temperature difference) is –40.05 mV/K, representing up to a fivefold increase over conventional n-type cells. The device also demonstrated excellent durability, maintaining consistent performance after 50 charge-discharge cycles.
The core of this solid-state cell comprises a conductive polymer, PEDOT:PSS, and a redox couple of Fe(ClO₄)₂/3. Electrostatic interactions between the negatively charged sulfonate groups (–SO₃⁻) of the polymer and the Fe²⁺/Fe³⁺ ions establish a stable structure, while perchlorate ions (ClO₄⁻) are free to move, facilitating ion diffusion and thermodiffusion effects that boost power output.
Professor Jang stated, “This research marks a new milestone in low-temperature waste heat energy harvesting and flexible energy conversion devices. It has the potential to serve as a self-powered system for wearable electronics and autonomous IoT devices driven solely by body heat.”
More information:
Jeong-Ye Baek et al, Solid-state n-type thermodiffusion-assisted thermogalvanic cells with unprecedented thermal energy conversion, Energy & Environmental Science (2025). DOI: 10.1039/D5EE01216C
Citation:
Solid-state device harvests body heat to power battery-free wearables and IoT sensors (2025, September 8)
retrieved 8 September 2025
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Tech
Skip the TSA Line: Where to Find Travel by Bus, Train, and Boat
Every year, without fail, the US experiences at least one major disruption in air travel due to severe weather, government shutdowns, software outages, or power outages—you name it.
Right now, a partial government shutdown has meant that thousands of Transportation Security Administration (TSA) workers have not been paid for several weeks, causing many to call out of work or quit. That has meant long security lines—more than three-hour waits—ensuing chaos at airports around the country. It’s unclear how long this mess will last, so it’s worth thinking about other options.
Flights are also expensive and hard on the environment. If you can take a bus, train, or ferry to your destination, why shouldn’t you? These travel search apps help you find routes and prices so you can compare them and make the best decision.
Wanderu
Best for Buses and Trains in the US and Canada
In the US and Canada, Wanderu is my go-to search aggregator for travel by bus or train (it works in Europe and the UK, too). Wanderu is your classic travel aggregator, looking up the schedules and prices across several bus and train operators, including Amtrak, BestBus, Flixbus, Greyhound, OurBus, Peter Pan, RedCoach, Vamoose, and others.
You see price comparisons at a glance, as well as options for upgraded class fares, departure and arrival times, and the location of each bus and train station, since sometimes you can save a lot of time by choosing one point over another. Filters help you narrow down your results based on your preferences, and you can book right from the app.
Omio
Compares Trains, Buses, Flights With Excellent Summaries
If you aren’t sure whether you want to travel by land or air, head to Omio. Type in your departure point, destination, and the date you want to travel, and Omio finds routes by plane, bus, and train. A concise summary at the top of the search results tells you the lowest fare and how long it will take for each mode of transportation, so you can make an informed decision quickly. Omio also shows whether the fare will be higher or lower if you travel on a different day of the same week, in case your dates are flexible.
Rome2Rio
Includes Comparison for Driving
Rome2Rio compares prices and times for travel by bus, train, flight, and driving yourself, based on estimated fuel costs. It works reasonably well for trips in the US and Canada. Rome2Rio touts itself as being for worldwide travel, though Europe and the UK seem to be its sweet spot. Elsewhere, take the approach of “trust, but verify,” and this app will take you places.
Virail
Compares Buses, Trains, and Flights
Virail is similar to Omio, comparing travel options by train, bus, and flight, with a neat summary of prices at the top of the search results, although it lacks the total travel time. For that, you have to scroll through the results. To book a ticket, Virail sends you to other websites, and you might have to do additional legwork to reserve your seat. It works reasonably well in the US and Canada (in testing, it got a little tripped up in Mexico), and does well for travel in Europe and the UK.
Vivanoda
Includes Flight and Carpool
Vivanoda (website only, no app) is similar to Omio, comparing all your options for getting between two points—and it includes flights, ferries, and carpool/rideshare options when applicable. The site operates out of the European Union and seems to work slightly better for travel in Europe and the UK than in the US and Canada, where it has some holes. (It didn’t find a direct flight between San Francisco and Vancouver, for example, even though there is more than one daily.)
Seat 61
Best Old-School Site for Trains and Bus Info Worldwide
Seat61, also known as The Man in Seat 61 (website only), has an old-school look and some of the best, most reliable information about traveling by bus and rail all around the world. Mark Smith, who runs the site, tells you exactly where in the world he knows about the train and bus routes: The site lists all the countries it covers on the left side, everywhere from Albania to Zimbabwe. He shares timetables, prices, and even includes photos, though his site is not a search aggregator, and you do have to go elsewhere to book. That said, it’s an excellent resource.
Tech
Lloyds admits coding fault exposed customer transactions | Computer Weekly
Lloyds Banking Group’s response to a request from the UK government’s Treasury Committee shows that a programming error was the root cause of a breach that exposed details of more than 114,000 mobile banking customers.
The bank said it has made goodwill payments totalling just over £139,000 to around 3,625 customers as of 23 March. It said it also submitted a formal notification to the Information Commissioner’s Office within 72 hours after the breach, in line with statutory timelines.
As Computer Weekly has previously reported, on the morning of 12 March, a fault in the Lloyds banking app enabled some customers to see the transactions of other customers. Customers of the group’s Halifax, Bank of Scotland and Lloyds Bank apps were affected by the security breach.
While the bank resolved the breach quickly, Meg Hillier, chair of the Treasury Committee, sent an email to Lloyds Banking Group’s group CEO, Charles Nunn, with the subject line “Improper disclosure of individuals’ account information”. In the email, Hillier described the incident as “an alarming breach of data confidentiality.”
The information she requested from the bank’s boss included details of the breach, how many customers were affected, whether customers could be identified and what steps Lloyds Banking Group has taken to encourage those who may have taken copies of data – of which they were not entitled – to delete those copies.
Jasjyot Singh, CEO of consumer relationships at Lloyds Banking Group, has now responded to the Treasury Committee’s questions. Singh stated that the incident was caused by an IT change made overnight between 11 and 12 March which introduced a software defect.
“The defect meant that when a customer requested to view their current account transactions, their transaction data was potentially visible to other customers who were simultaneously – within small fractions of a second – requesting access to their own transactions,” Singh said.
The bank has now established that the defect was in the design of the code used to update the application programming interface (API) used by the app. Singh said the bank is reviewing why this individual defect was not detected by its design, quality assurance and testing processes.
According to Singh, a maximum of 447,936 customers who viewed their transaction list during the affected time period may have been presented with other people’s transactions or may have had some of their transactions presented on another customer’s transaction list. The bank has estimated that 114,182 customers clicked through to view the detail behind individual current account transactions during that time and may have been presented with information about individual payments.
Singh assured the Treasury Committee that the bank’s fraud and cyber monitoring processes has seen no evidence of misuse or malicious activity as a result of the incident. “Based on our assessment of this incident, we have not identified evidence that customers have suffered financial loss, and no customer has reported a financial loss arising from the incident at this stage. Accordingly, we have not made compensation payments on this basis,” he stated in the letter.
Tech
Colt announces subsea, terrestrial network routes | Computer Weekly
Financial services firms, content providers, neocloud companies and hyperscalers are all claimed to be among the primary beneficiaries of a digital infrastructure from Colt Technology Services linking the US West Coast to Asia.
The announcement marks the latest phase of the global digital infrastructure company’s global network expansion, and the investment it made in the infrastructure is said to support customers’ international growth strategies and include a transpacific subsea cable route linking the US and Japan.
Colt says the expansion elevates it from its position as the largest European B2B fibre provider to one of the largest in the world, reinforcing its role as a key player in the global digital infrastructure market.
The enhanced infrastructure is seen by Colt as strengthening its network resilience for organisations – by delivering secure, high‑performance backup and routing options for mission‑critical applications. Congested networks mean lags, delays and service interruptions – expensive setbacks which stall progress.
Colt’s network investment is designed to directly addresses surging demand driven by AI traffic. The infrastructure is attributed with giving customers greater choice of offerings, performance and cost, especially for busy transpacific routes already under pressure from rising traffic volumes.
As part of the investment, Colt will deliver a transpacific backbone route through Juno – one of the world’s newest and most advanced subsea cable systems – connecting Tokyo, Japan to Los Angeles on the West Coast of the US.
Having come into service in May 2025 and operated by Seren Juno Network Co, the Juno cable is around 11,700km (7,270 miles) long and engineered to deliver up to 350Tbps across 20 fibre pairs, using next-generation Space Division Multiplexing technology. In Japan, it lands at Minamiboso (Chiba Prefecture) and Shima (Mie Prefecture), connecting with Grover Beach, California. It extends to terrestrial points of presence in Tokyo, Osaka, Los Angeles and San Jose.
The Colt network is intended to offer customers a diverse route, connecting Colt’s existing terrestrial networks in Japan and the US, providing greater resilience and higher bandwidth options to provide greater resilience on transpacific services.
This is said to make the services ideal for businesses with global operations across Asia and the US. Another benefit is said to be an expansion in the global digital footprint, extending its “on-net” capabilities. Colt can connect directly into multiple sites across Tokyo, with on‑net coverage throughout the city’s key metro datacentres.
Commenting on the expansion, Buddy Bayer, chief operating officer of Colt Technology Services, said: “The world’s economies run on digital infrastructure, but there will come a point when existing capacity across some routes isn’t enough. This risks disrupting or even reversing the progress countries have made in connecting markets, organisations and societies. At Colt, we have a deep commitment to solving problems for our customers so they can grow and scale. This investment in our digital infrastructure connecting the US West Coast to Tokyo, Japan not only solves the capacity problem for our customers – it’s also a gateway to global growth.”
News of the new subsea infrastructure comes shortly after Colt announced an expansion and investment into new routes connecting the East Coast of the US to Europe. Specifically, the low-latency routes along the US East Coast and between the US East Coast and Europe are designed to “supercharge” capacity for customers as AI traffic surges across what is said to be the world’s busiest data pathway.
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