Chances are after you’ve had that brand new iPhone for a few months, the battery life no longer makes it to the end of the day, particularly if that day includes a lengthy work-out playlist. One company with just five days left in their Kickstarter campaign has a green solution—a phone charger that creates energy from motion.

AMPY, a charging device invented by PhD students at Northwestern, harnesses energy from all directions of movement and turns it into battery life. The simple, pocket-sized, wearable device provides about three hours of smartphone battery life for the average 10,000 steps per day. For the jogger, a 30 minute run will also provide the three hours of smartphone charge, about 24 hours on a smartwatch, and 72 hours on a fitness tracker, according to the product’s website. AMPY charges devices via any standard USB cord. Perhaps most miraculously, the device is able to store about a week’s worth of movement for several months. There is no pressure of a draining battery to use the energy until needed. In a pinch, AMPY also connects to the wall like a traditional back-up battery to add hours of use to your smartphone.

AMPY come with an app that allows users to track generated battery life, calories burned during movement, and carbon footprint offset by using the product.

A device like AMPY is great not only because it’s green, but because it's a practical device with wide-spread appeal, it's also a big selling point for an application of renewable energy. It is even more convenient than less eco-friendly alternatives. The invention has clearly peaked the interest of many with a Kickstarter campaign that has already raised more than double the goal $100,000 with $268,989 raised (as of this morning) and more than 2,000 backers.

Here is a video all about AMPY and check out their Kickstarter page this week.