A phenomenon called "evanescent coupling" could allow electronic gadgets to start charging themselves as soon as their owner walks into their home or office.

Researchers have been looking for a way to make a wireless charger for some time. One idea is to use electromagnetic induction – passing an electric current through a coil to create a magnetic field that induces a current in a neighbouring coil.

This is the way devices like electric toothbrushes are charged, and has been proposed as the basis of a universal recharger pad before (see One charger pad could power up all gadgets).

The snag as far as mobile devices are concerned is that the charger and device must be in close contact with each other for it to work. Alternative schemes - for instance, transmitting electromagnetic waves in all directions to reach any device in a room - would be hugely wasteful.

Great. Now all we need is the Mecha.