How outdated phones can power smart cities and save seas

Researchers at the University of Tartu Institute of Computer Science introduce a novel approach to reducing electronic waste and advancing sustainable data processing: turning old smartphones into tiny data centers.

According to Science Daily, each year, more than 1.2 billion smartphones are produced globally. The production of electronic devices is not only energy-intensive but also consumes valuable natural resources.

Additionally, the manufacturing and delivery processes release a significant amount of CO2 into the atmosphere. Meanwhile, devices are aging faster than ever — users replace their still-functional phones on average every 2 to 3 years. At best, old devices are recycled; at worst, they end up in landfills.

Although the most sustainable solution would be to change consumer behavior and consider more carefully whether every new model truly requires replacing the old one, this is easier said than done.

Therefore, alternative solutions are needed — such as extending the lifespan of devices by giving them an entirely new purpose.

This is precisely the approach tested by researchers Huber Flores, Ulrich Norbisrath, and Zhigang Yin from the University of Tartu’s Institute of Computer Science, along with Perseverance Ngoy from the Institute of Technology and their international colleagues.

“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,” explained Huber Flores, Associate Professor of Pervasive Computing.

They demonstrated that old smartphones can be successfully repurposed into tiny data centers capable of efficiently processing and storing data.

They also found that building such a data center is remarkably inexpensive — around 8 euros per device.

These tiny data centers have a wide range of applications. For example, they could be used in urban environments like bus stops to collect real-time data on the number of passengers, which could then be used to optimize public transportation networks.

In the project's first stage, the researchers removed the phones’ batteries and replaced them with external power sources to reduce the risk of chemical leakage into the environment.

Then, four phones were connected together, fitted with 3D-printed casings and holders, and turned into a working prototype ready to be re-used, fostering sustainable practices for old electronics.

The prototype was then successfully tested underwater, where it participated in marine life monitoring by helping to count different sea species.

Normally, these kinds of tasks require a scuba diver to record video and bring it to the surface for analysis.

But with the prototype, the whole process was done automatically underwater.

The team's results show that outdated technology doesn’t have to end up as waste.

With minimal resources, these devices can be given a new purpose, contributing to the development of more environmentally friendly and sustainable digital solutions.

“Sustainability is not just about preserving the future — it’s about reimagining the present, where yesterday’s devices become tomorrow’s opportunities,” commented Ulrich Norbisrath, Associate Professor of Software Engineering.