Could your footsteps one day charge your phone? Meet Angelo Casimiro, the 15-year-old behind the invention

What if your morning walk did more than burn calories? What if every step you took generated electricity that could help power your gadgets?

That question inspired Angelo Casimiro, a teenager from the Philippines, who designed a fully functional pair of shoes that generates electricity while the wearer walks, runs, or plays sports. He built the prototype at just 15 years old, showing how everyday movement could become a source of clean energy as the world looks beyond fossil fuels, according to a report by The Times of India.

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As the global energy landscape changes and researchers warn that traditional energy sources could diminish by 2088, innovations like wearable energy-harvesting technology are attracting growing interest.

Casimiro realised that billions of steps are taken every second around the world, and wondered what if this movement could be used to power everyday gadgets. To make that possible, he placed two pressure-sensitive generators on each insole, allowing the shoes to capture more energy without increasing their size.

What is the science behind electricity generated by footsteps?

The technology works using a phenomenon known as piezoelectricity.

As Vesa Aho explains in the thesis Insole Energy Harvesting from Human Movement Using Piezoelectric Generators, the effect was first discovered in 1880 by the Curie brothers.

The term is defined as "certain materials that induce an electric field when they come under mechanical force or pressure." When you step on these materials, their internal structure deforms, causing ions to move and generate an electric charge.

This process transforms mechanical energy into electrical energy. In simple terms, pressure equals power.

The energy harvester is placed in parts of the shoe that experience the most force, such as the heel or the ball of the foot. Every time your heel strikes the ground, a small pulse of electricity is produced, which can either be used immediately or stored for later use.

Which materials can turn footsteps into electricity?

According to Vesa Aho, there are four main groups of piezoelectric materials: single crystals, ceramics, polymers, and composites.

One of the most widely used ceramics is PZT, which is popular because it is affordable and highly efficient at generating electricity. However, it is also rigid and brittle, meaning it can crack if the shoe bends too much. It also contains lead, a toxic substance.

Scientists are therefore also exploring polymers such as PVDF (polyvinylidene fluoride). These materials are much more flexible and durable, making them suitable for wearable products because they can bend and twist without breaking. The drawback is that they generate much less electricity than ceramics.

Researchers are now developing composites to combine the flexibility of polymers with the high power output of ceramics.

Can these shoes actually charge your smartphone?

The award-winning essay in the Trust for Sustainable Living notes that Casimiro's prototype could fully charge a 400 mAh battery after roughly eight hours of jogging.

While that is a remarkable achievement for a teenager, it also highlights the current limitations of the technology.

Vesa Aho points out that modern smartphones, including iPhones, have much larger battery capacities. At today's power levels, typically ranging from 1 to 10 milliwatts per step, it could take several days of continuous walking to fully charge a high-end smartphone.

For now, the technology is far better suited to powering wearable health monitors, pedometers and location-tracking sensors, which require much less energy.

How is the electricity stored?

Electricity produced by footsteps comes in short bursts, so it cannot be used directly. It first needs to be stored.

Traditionally, this has been done using capacitors, which charge and discharge quickly. However, they also lose their charge rapidly through leakage.

Rechargeable batteries are another option, but they have limited lifespans and often contain hazardous chemicals.

A more promising solution, according to Vesa Aho, is the supercapacitor. These devices can store large amounts of energy, recharge repeatedly without wearing out, and safely hold the electricity generated during activities such as a morning run until it is needed later in the day.

Why inventions like this matter

Casimiro's project is part of a growing field known as energy harvesting—the process of capturing small amounts of energy from sources such as heat, light or movement that would otherwise go to waste.

The collected energy can extend the battery life of portable electronic devices and even power low-energy gadgets on its own.

While one person's footsteps may not seem significant, the combined movement of millions of people could generate meaningful amounts of clean energy. As 2030 draws closer and countries push for cleaner technologies, innovations like energy-harvesting shoes offer a glimpse into how everyday actions could contribute to a more sustainable future.

Casimiro's invention is a reminder that the next breakthrough in clean energy may not come from a giant power plant, but from the simple act of taking a step.