We have covered exoskeletons here before; typically, these strap-on devices help paralyzed people walk on their own. A group of students at Rice University are working on a device that doesn’t provide power to the wearer, but instead harvests energy from the wearer’s movements while walking. This energy is stored in a battery as electricity, that could then be used to power a wearable Health Tech device or even a medical implant.
The students started with a standard medical brace, and then used the rotational motion of the knee joint to spin a motor that produces an electrical current. They had to use capacitors to level the output so that they could charge a battery safely. Their device produces 4 Watts of energy, and is comfortable enough to be worn for extended periods. They hope to develop a way to transmit the power to the battery wirelessly.
The group has already reduced the size of the generator to make it less likely to collide with obstructions. It’s possible to see how the design could be made smaller still, and could eventually become a practical way to harvest energy from the simple act of walking.