How many times has your cell phone run out of juice and you don't have your charger? For some of us, it happens all the time. That's because smart phones use a lot of energy and run out quickly.
But a group of college students has developed a charger that uses "people power" to keep devices on.
"Everybody's had an issue where their smart phone has run out of power at the worst possible time," says Tejas Shastry.
It turns energy from a person's physical movement, called kinetic energy, into battery power.
From your pocket or your purse, Ampy charges as you move throughout the day. When your battery gets low, connect the device to your phone and charge it up.
The trio claim that running for 30 minutes, cycling for an hour, or walking 5,000 steps provides enough "people power" for one hour of active smart phone use.
This isn't the first movement-inspired charger to hit the market.
"So there are other products on the market, but they're the size of a paper towel," says Smith
Ampy also works with other devices that charge with a USB port.
Its smaller size has attracted 2,500 pre-orders.
But at nearly $100, some wonder if Ampy's convenience is worth the hefty price.
"There's that cost factor, especially when a spare battery doesn't cost that much you can get a spare battery for $25 or less," says Bridget Carey of CNET.
For consumers who need to stay connected, Ampy provides an on-the-go way to power up in a pinch.
The Ampy inventors are current building prototypes with a 3D printer.
They hope to start mass producing Ampy by the summer.