The skin of a robot has to fulfil two apparently opposing needs: it must be elastic enough to lend the robot human-like dexterity, and yet carry enough wiring to allow it to sense its environment. Of course. If engineers connect the robot's sensors to metal wires these will break when the skin stretches. An emerging answer might be to embed a broad corrugated metal film in an elastic covering instead. Electrical engineers Sigurd Wagner and Stephanie Lacour at Princeton University have developed a kind of connector incorporating broad metal strips that, unlike wires, can stretch up to twice their length and still conduct electricity. They think it will be ideal for use in robot skin. Metal films are normally quite brittle, snapping when stretched more than one per cent of their length. Wagner and Lacour say their elastic metal film connectors based on gold film just 25 nanometres thick can stretch by at least 15 per cent in the rubbery silicone membrane in which they are embedded. This is because the gold film is corrugated, so it can be flattened out or compressed and still conduct electricity. And it stretches even more than they expected. Source New Scientist.