Piezoelectric generator problems

hello i have interested in alternative energy sources for a while and decided to try getting electricity by pressing on piezo as i saw someone else do in this video:https://www.youtube.com/watch?v=ACsy6xSIBm8 so i bought myself some normal piezo buzzers on internet and tried lighting an L.E.D with them... that didn't work so i tried charging a capacitor and testing voltage but that gave nothing. I'm really disappointed does anyone know how i could make it work. (maybe other kinds of piezo i dont know :confused: )

Piezo devices are extremely high impedance, so whilst they will generate a voltage when pressed, you cant power anything with them, as they cant deliver any meaningful current. You need an amplifier with a hi impedance input to do anything useful with a piezo.