A team at the University of Pennsylvania have developed a power-generating backpack. Dubbed “Suspended-load Backpack”, the device converts mechanical energy from walking into electricity – up to 7.4 Watts – more than enough energy to power several portable electronic devices at once.
The backpack is based on a rigid frame pack, but than being rigidly attached to the frame, the sack carrying the load is suspended from the frame by vertically oriented springs. It is the vertical movement of the backpack contents that provides the mechanical energy to drive a generator mounted on the frame. “As humans walk, they vault over their extended leg, causing the hip to rise 5-7 centimeters on each step. Since the backpack is connected to the hip, it to must be lifted 5-7 centimeters,” explains biologist Larry Rome. “It is this vertical movement of the backpack that ultimately powers electricity generation.”
The amount of power generated depends on how much weight is in the pack and how fast the wearer walks. With loads of 40 to 80 pounds, a wearer could constantly generate as much as 7.4 Watts while moving at a steady clip. Cell phones – or night vision goggles – require less than one Watt to power.