Old Smartphones Get New Life as Tiny Data Centers

This article is part of our exclusive IEEE Journal Watch series in partnership with IEEE Xplore.

Data processing for AI models requires a lot of computing power, which usually means bulky, expensive data centers. But researchers are studying how to distribute complex computing tasks among a range of affordable, not-so-powerful devices for more flexibility and ease of use. The approach is especially handy for IoT applications that need to crunch data at unusual or out-of-the-way locations.

In a recent experiment, Estonian engineers found that smartphones more than 10 years old, when hacked to work together as a single self-organized unit, can handle many such tasks, including image recognition, with unexpected ease. The researchers think the approach could reduce the cost of IoT computing and open a new avenue for electronics recycling to help tackle the world’s growing electronic waste problem.

“Smartphones are really well designed for high-energy processing,” says Huber Flores, an associate professor of pervasive computing at the University of Tartu in Estonia. “They are also very well optimized to not overheat and are very efficient in handling heavy data-processing applications.” Flores and his colleagues published their results in an early-access paper published in IEEE Pervasive Computing.

How to Build a Data Center Out of Old Phones

Old smartphones may seem like an unlikely option for collaborative computing: Their old batteries drain quickly and their outdated operating systems have tons of unpatched security vulnerabilities. But these shortcomings can be overcome. And even old smartphones feature potent CPUs and fast-operating memory, which enables them to comfortably outperform popular IoT-specific devices such as the single-board Raspberry Pi computer, according to Flores—especially when made to work together. These smartphone-based data centers can run image-recognition algorithms, host websites, or crunch company data. Reusing old smartphones in this way could thus help reduce the cost of IoT projects but also tackle the ballooning problem of e-waste.

The WEEE Forum, an international association promoting electronic-waste responsibility, estimates that some 5.3 billion mobile phones get thrown into waste every year. Currently, the possibilities of their reuse or recycling are limited. At best, the electronic devices are sent to waste-processing facilities, where they are stripped of precious metals such as gold or palladium that can be resold and reused. The rest are either incinerated or thrown into landfills, where they leak toxic chemicals into the environment.

In their study, the researchers connected four 10-year-old Google Nexus smartphones, making one serve as a “master” and the three others as data-crunching “workers.” The master interacts with sensors or receives tasks from a controller and redistributes those tasks to the individual workers, facilitating the collaborative data processing.

In an 8-hour experiment conducted off the coast of the Portuguese island of Madeira, one such mini data center connected to a high-resolution camera and placed inside a watertight bubble successfully counted marine species 25 meters below the surface of the Atlantic Ocean.

Linked smartphones can provide robust computing power to sensors in challenging environments.University of Madeira

The researchers placed the smartphones into a 3D-printed rack and connected them to an external power source. Then they overrode the smartphones’ operating systems with the open-source Linux-based Postmarket OS, on top of which they built their unique applications. The whole setup cost about €8 (US $9.30), Flores said, compared to the more than €50 for the latest basic Raspberry Pi.

“These phones, you can just get them from trash,” says Flores. “All you have to do is to buy a module to regulate the voltage that you put into the phone from another source. Then you install the open-source system to control the hardware and make the smartphones work together and you have a tiny data center that can be useful for many applications.”

The researchers are developing another application, in which the data center would track the flow of people in a city center by processing measurements from an infrared sensor. In another experiment, they want to install such a data center on a ground robot to serve as a data-processing hub for a swarm of flying drones.

“The flying drones can collect data with a camera, looking at a territory, and then this can get analyzed on the ground with the help of these tiny data centers,” says Flores. “It’s actually very practical as well.”

Flores thinks the technology could also be of use to cash-strapped early-stage companies that need to host websites or run data analytics but don’t have sufficient funds to rent space in cloud-based data centers.

The Limitations of Smartphone Data Centers

Turning old phones into data centers, however, has its limits, admits Flores. There was a reason why the team chose Nexus phones for the experiment. The open-source line, discontinued in 2016, featured a modular design that was easy to take apart. Since then, however, most manufacturers have turned to manufacturing approaches that make it hard to remove components without damaging the smartphone. The software, too, has become more proprietary and difficult to override.

“If it’s too difficult to hack and repurpose the phones, then the whole thing becomes more costly,” says Flores.

Flores hopes, however, the research might inspire regulators in the future to require gadget makers to opt for design approaches that are more reuse-friendly to help reduce e-waste.

“It’s more about policymakers and governments to enforce that,” says Flores. “The manufacturers are not going to do it unless there are guidelines telling them so.”

According to the World Health Organization, electronic waste is globally one of the fastest growing waste streams. In 2022, for example, 62 million tonnes of old electronics have been disposed of around the world with only about 22 percent properly recycled. Electronic waste is a significant source of heavy metal contamination in the environment, leaking lead, cadmium, and mercury into the soil and groundwater.

This article appears in the August 2025 print issue as “Old Smartphones Get New Life as Tiny Data Centers.”