We know from the past the wristwatches which are winding themselves, drawing energy from hand movements. Recently the study went on: a joint project of the Chongqing University of Technology in Chongqing and the Sichuan Academy of Engineering Physics created a bracelet that transforms the human wrist into electrical energy and accumulates it so that it can charge itself and even charge the batteries of mobile devices.
Inside the bracelet there are two moving magnets and copper coils. Moving magnets creates a voltage. "The biggest advantage of this bracelet is that it can transform the translational movement into a circular one, using the initial position of the magnets," explains Zhiyi Wu, responsible for the project. The translation movement (in physics) involves moving the molecule relative to the other. The bracelet uses movement in any direction. The amount of energy produced depends, of course, on the intensity of the movements. For now, the power is measured in single milliwatts.
Such a bracelet could provide additional power for constant monitoring the health of the wearer. It could also be a kind of powerbank, for example a smartwatch. Will it enter into widespread use? It's hard to say because everything depends on the demand for such power. If the invention is properly advertised, there may be a need for it. Not all inventions, even seemingly very attractive, come into wide use. Otherwise, it may be just a prototype for further research on the energy of "nothing"