Intel researchers have developed a robotic hand that is able to sense the general shape of objects before interacting with them:
The tips of its fingers send out a weak electrical impulse that objects interfere with, giving the hand a rough idea of what it's about to grasp. Using electrolocation, as it's known, is common in fish, particularly sharks, which detect electric fields better than any other animal. Think of it like sonar with electricity.
Joshua Smith, an Intel researcher working on the project, said that electrolocation only provides coarse data about the shape of objects, but that this actually worked very well for grasping tasks. Using the technique is one means by which his team is trying to give robots what they call "Pre Touch," a sense that has a longer range than touch but a shorter range than vision. Perhaps a catchier name would have been the sixth sense.
Here's a video from the Research@Intel Day event at the Computer History Museum in Silicon Valley: