Angelo Casimiro, a 15-year-old student from the Philippines did a little science experiment to charge smartphones or any portable device by simply walking.
Using piezoelectric transducers, Angelo Casimiro came up with a system that can harness the energy produced with each step made. He developed this idea and turned it into a project that he submitted at the 2014 Google Science Fair.
Basically, he attached a powerbank to some old sneakers together with diodes and transducers to come up with a pair of “smart shoes” that has the energy needed to power up a smartphone. There’s a list of everything he used if you want to try it out yourself. You can also watch the video for a more detailed explanation on how it works.
Update: It has come to our attention that there were three students from Philippine Science High School who first did this project, and in fact won an award at Project Tuklas around February of 2013. There must have been a conflict of sources.