Researchers have developed a low cost way to turn discarded smartphones into tiny data centres that can support real world environmental and civic projects.
Why Old Smartphones Still Matter
More than 1.2 billion smartphones are produced every year, yet most are replaced within two or three years even when they remain fully functional. The environmental cost of this rapid cycle is significant. Smartphone manufacturing is energy intensive, relies on mined materials such as cobalt and lithium, and contributes to the 62 billion kilograms of global e-waste recorded in 2022. Only a small proportion is formally recycled, so millions of phones end up forgotten in drawers or sent to landfill.
Consequently, many sustainability groups have long been arguing that extending device lifespans is one of the most effective ways to cut electronic waste, since the majority of a smartphone’s carbon footprint is created during manufacturing. Until recently, extending that lifespan usually meant refurbishment or resale. The latest research from the University of Tartu (in Estonia) shows that a third option is now possible, one that reuses phones in a completely different role.
The Idea Behind Tiny Data Centres
The new approach comes from a team of European researchers whose study in IEEE Pervasive Computing explains how old smartphones can be reprogrammed and linked together as miniature data centres. The aim is not to compete with traditional cloud computing, but to show that many small and local tasks do not require new hardware at all.
The team, led by researchers including Huber Flores, Ulrich Norbisrath and Zhigang Yin, began by taking phones that were already considered e-waste. The devices were stripped of batteries and connected to external power supplies to avoid chemical leakage risks that can arise when batteries degrade. This small step is important for long term deployments, since lithium-ion batteries can swell or leak when left unused for years.
Four phones were then connected together, placed inside a 3D printed holder, and configured so that the system acted as a single working prototype. According to the researchers, this entire process cost around €8 per device, making it far cheaper than installing new embedded computing hardware for similar tasks. As Flores explains, “Innovation often begins not with something new, but with a new way of thinking about the old, re imagining its role in shaping the future.”
Putting Repurposed Phones To Work
The first major test took place underwater. The tiny data centre was used to support marine life monitoring by processing video and sensor data directly below the surface. This type of survey work usually depends on scuba divers recording footage and bringing it back for analysis. The prototype allowed that analysis to happen automatically on site, reducing labour, shortening processing time, and avoiding the need to send large data files across networks.
Edge Computing
This approach is known as edge computing, where data is processed close to the source rather than in distant data centres. Repurposed smartphones are well suited to this because they are built to handle local storage, low power processing and real time tasks. It means they can support use cases where traditional servers would be excessive or impractical.
Also On Land
It should be noted that there are some clear examples on land too. For example, the Tartu team highlights how a unit placed at a bus stop could gather anonymised information about passenger numbers, waiting times and traffic levels. Transport agencies could use that real time data to improve timetables or plan new routes. It is the same principle behind many smart city projects, but achieved with hardware that already exists.
The researchers also point towards environmental monitoring, urban air quality measurements, small scale agricultural sensing, and certain machine learning applications where data volumes remain modest. These tasks do not demand the full power of modern workstations, yet they still require reliable processing in locations where installing new equipment is expensive or unnecessary.
A Sustainability Case With Wider Implications
The argument for tiny data centres is not only technical, but is also rooted in sustainability thinking.
For example, smartphone production is responsible for significant emissions and resource extraction. Therefore, extending the life of older devices makes use of computing power that would otherwise sit idle or be discarded. In a world where global demand for computing continues to rise, repurposing offers a practical way to satisfy some of that demand without adding new manufacturing emissions.
Ulrich Norbisrath, one of the researchers involved, summarises this perspective clearly: “Sustainability is not just about preserving the future, it is about reimagining the present, where yesterday’s devices become tomorrow’s opportunities.”
The project reflects a broader trend within the digital sustainability community, where attention is turning towards resource efficiency and circularity. From longer software support periods to designs that support repair and reuse, the goal is to reduce reliance on a constant flow of new devices. Repurposing smartphones as micro data centres adds another practical option to that toolkit.
Practical Challenges Still To Address
Although this sounds like real progress, the researchers are realistic about the obstacles. For example, one major hurdle is the wide variety of smartphone models. Chipsets, memory sizes and firmware differ significantly across brands and generations, making it difficult to build a universal method for bypassing hardware restrictions. The study calls for the creation of tools that are hardware agnostic so that more people can repurpose devices without advanced technical knowledge.
Energy supply is another issue. Although the devices draw little power individually, long term deployments in remote locations require stable energy sources and protection from moisture, heat and physical damage. This makes the design of the 3D printed casing and supporting hardware an important part of the overall system.
Security also needs careful thought. For example, smartphones were never designed to operate as unattended networked devices, so any repurposed system must have secure software, strong update controls and physical safeguards. Without this, there is a risk that poorly maintained clusters could introduce vulnerabilities.
The team stresses that their prototype is really a proof of concept, i.e., it shows what is feasible today and identifies where future development is most needed, including standardised tools, easier configuration processes and larger scale trials.
What Does This Mean For Your Organisation?
UK organisations are under growing pressure to reduce waste, cut emissions and make better use of the resources they already hold. Repurposed smartphones could present a practical way to help support those goals, especially for businesses that cycle through large numbers of devices each year. Treating retired phones as reusable computing assets rather than waste creates immediate value and avoids the environmental cost of manufacturing yet another round of hardware. It also offers a route to experiment with local data processing without committing to major capital spending.
For many firms, the most relevant opportunity lies in small scale, on site tasks where data needs to be collected, processed and acted on quickly. Old smartphones can support building management, environmental monitoring, simple analytics and other operational jobs that do not require full server deployments. This keeps data close to the source, avoids unnecessary cloud usage and aligns with wider efforts to improve energy efficiency. The approach also speaks directly to the sustainability strategies now expected by regulators, investors and customers who want evidence that companies are reducing electronic waste in credible ways.
There is a clear benefit for local authorities, utilities and public services too. Tightly constrained budgets mean that projects often stall for lack of affordable hardware. Repurposed phones give these stakeholders a way to test new ideas at low cost, from monitoring passenger numbers to gathering air quality data. This helps build evidence, speed up innovation and guide investment decisions without locking into expensive platforms from day one.
Technology suppliers and service partners may also find value in developing tools that make repurposing easier. Businesses increasingly want flexible, lower carbon digital solutions and the research points towards a future market for hardware agnostic software that can unify mixed phone models into consistent micro data centres. For the UK’s growing sustainability and digital sectors, this represents a fresh area of opportunity.
The wider message for all stakeholders is that existing technology still has untapped potential. Repurposing does not replace secure recycling or responsible disposal, but it does extend the useful life of devices that would otherwise remain unused. For UK businesses looking to reduce waste, cut costs and support their environmental commitments, the University of Tartu’s work shows that old smartphones can play a meaningful role in creating a more resource efficient digital environment.