When Hahna Alexander set out to create a shoe that could charge a battery, she had no idea what challenges lay ahead of her.
The inventing part went smoothly enough. Like many first-time inventors, she had a good idea and a passion for her work. She successfully invented a shoe that harnesses energy from each step the wearer takes. That energy can be used to charge a battery.
Alexander spent years developing the technology and even co-founded her own company called SolePower. But when she finally tested her prototype, she quickly discovered that people would rather just carry a backup battery than bother with a self-charging shoe.
It's fair to say she was disappointed.
But her failure challenged her to go back to the drawing board and come up with something that did more than charge a battery. She and her team invented a "smart shoe" that can track GPS location, step count and even temperature, and share that information on the Internet. All of the devices in the shoe are constantly powered by walking.
Alexander hopes that the shoes can help people who work in search and rescue, high-risk industry and the military. For example, in the case of an emergency the shoe can report the location of the wearer to people trying to help. It could even report the location of troops in battle.
"The failure taught us an important lesson," she says: "You have to invent something that people can't live without."