An electromagnetic generator comprising a multilayer assembly of a first layer carrying at least one magnet, a second layer carrying at least one coil, and a third layer carrying at least one magnet, the at least one magnet of the first and third layers being configured to define therebetween a region of magnetic flux in which the at least one coil is disposed, at least one of the layers being shaped to define a respective displaceable portion thereof which is displaceable by vibration of the electromagnetic generator thereby to cause relative movement between the coil and the magnets and generate an electrical current in the coil.