This Wearable Gadget Turns Your Footsteps Into Battery Life For Your Phone

The Ampy gives you motivation to get moving and solves the problem of your device always running out of battery.

Most fitness trackers try to inspire action by counting your steps. But a new wearable adds another layer of motivation: As you move, the device captures that energy and stores it to later charge your phone.


The wearable, called Ampy, was inspired by the fact that as devices like smartphones get smarter, the batteries inside them haven’t kept up. The more addicted you are to your phone, the less likely it is that it can make it through the day before plugging in.

“We set out to solve a problem that a lot of us have: Your smartphone dies before the end of your day,” says Tejas Shastry, CEO of Ampy. “We were all active people, so we thought, is there a way to capture the kinetic energy that we put into daily activities to charge our phones?”

A typical city dweller without a car can easily walk 10,000 steps in a day, enough to generate three hours of battery life for a smartphone, or 24 hours of battery life for something like a smart watch. A half-hour run or an hour-long bike ride can double that amount of power. Even smaller motions, like fidgeting at a desk, add to the total.

Ampy straps on an arm as you’re exercising, or can slip in a pocket or bag the rest of the time. It weighs about as much as a phone. The battery inside can store power for months.

The designers think that the device will make people more likely to move. “We definitely see an opportunity to track a metric that means something more tangible to you,” says Shastry. “It’s great motivation when you get something for the work you’re doing.”

The device comes with an app that shows the number calories you’ve burned, the amount of energy you’ve created, and how much you’ve trimmed your carbon footprint by avoiding wall outlets.


Eventually, the technology could be integrated directly into some devices to help keep them charged automatically. “It’s applicable to a lot of different form factors and a lot of different scales,” says Shastry. “We’ve already seen opportunities to integrate our technology into new wearable devices to provide some or all of the power requirements.”

Still, don’t expect to see this built into your next phone, as future devices become even more power-hungry. Even the most active people probably aren’t quite active enough to keep a smartphone fully charged all the time.

Ampy is finishing a crowdfunding campaign on Kickstarter and should begin shipping next summer.


About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley.