Embedded inside it is a batteryless RF switch, and the way it works is that upon the release of the spring mechanism inside, a tiny bit of power is generated for the 2.4GHz RF transmission ( ZigBee compatible), and whatever device is connected to the RF control outlet on the other end will receive the on or off signal.

ENGADGET: Mitsumi exhibits micro-vibration power generator and batteryless RF switch (video)

The entire package, including two picosats and their spring-loaded ejection mechanism, weighs 3kg.

ECONOMIST: Picosatellites

The spring is wound for half a minute, and then unwinds over six minutes, charging a battery in the process, and providing enough energy to run the radio for an hour. (This means the radio's spring-controller circuit is no longer necessary.) Thus, Freeplay has switched from making solely spring-powered devices to making battery-powered devices that are equipped with a clockwork mechanism for recharging and emergency use.

ECONOMIST: Clockwork technology