RF tag has 200km range in free space

Called AGITATE, the device is currently the size of a 5p piece. It requires no battery: when shaken, it converts mechanical energy into radio signals which can be tracked through walls and up to 20km in built up areas. In free space, the device is said to have an estimated range of 200km. Peter Lockhart, Roke's future technology manager, said: "As with many of the best inventions, AGITATE was developed by accident. But thanks to inventive and creative minds, the team recognised a potential application and has brought that to fruition, developing a simple, yet highly usable, technology." According to Roke Manor, AGITATE could be produced for a few pence per unit and would have a broad range of tracking applications. Potential uses might include a low cost method of monitoring and regulating the use of lifejackets, with built in man overboard capability; remote sensing for flood monitoring and alerts; in the industrial sector, for remote sensing of motion and vibration fault detection in harsh environments; in the retail sector, as security tags on high value goods; and in the healthcare sector, for patient tracking. Trials have been conducted in the UK across 26km of variable terrain and Roke is now looking to miniaturise AGITATE and to increase its rf output power.