Coiled and ready to strike

DRONES may one day transform the way parcels are delivered, crops monitored and suspects apprehended. Those who talk up these possibilities, though, often neglect to mention the drawbacks of such robot aircraft—one of which is that most cannot fly for more than a quarter of an hour before they need to find a human being to swap their batteries for them or plug them into an electrical socket.

Joshua Smith, a computer scientist at the University of Washington, in Seattle, hopes to change that. In May he started a company called Wibotic that plans to recharge drones (and also earthbound robots) without them having to establish an awkward physical connection with a plug. A ’bot whose batteries were low would simply manoeuvre itself to within half a metre or so of a recharging station to top them up. LaserMotive, another Seattle-based company, is even more ambitious. It is developing a system designed to replenish the batteries of drones that are still aloft, using lasers and photovoltaic cells.