No, you cannot power up devices with magnets. Magnetic field is not the same as ELECTROmagnetic field. Look up how generator works. You need a magnet and a coil of conducting wire(copper) and they have to be moving in relation to one another. Like magnet being turned by water wheel. Magnetic field of the magnet moves electrons, because they are negatively charged and far away from the core of an atom and therefore can be moved (attracted to the positive pole of the magnet) Moving electrons create an ELECTROmagnetic field in the wire coil.