Plenty of work has gone into making robots that can see and hear. But what of their other senses? Now researchers have created a prototype electronic skin that may one day help robots sense pressure and temperature, helping them to operate independent of human control.
Getting electronic sensors to detect pressure and temperature is not hard. Silicon-based devices have been doing this for years. Although silicon is excellent for making small, high-speed transistors that make up the core of the sensors, it's not well suited for networks of devices that cover large areas, as would be needed for robotics and other applications. For these uses, researchers have recently turned to fashioning transistors, diodes, sensors, and other electronic components from electrically conductive plastics and other low-cost organic materials.
Last year, a team led by Takao Someya, an electrical engineer at the University of Tokyo, made networks of pressure sensors from a sandwich of electrically conductive, insulating and semiconducting films coated atop one of two plastic films called polyimide and poly(ethylenenaphthalate). However, these devices were only modestly flexible. So for their current effort, the team used an automated hole-punching machine to create a web shaped network that could stretch and twist. The researchers even layered their sensor network atop an egg to show that it could conform to the shape and still function, as they describe online this week in Proceedings of the National Academy of Science. What is more, the team made a similar network composed of temperature sensors.
The new work is "is an example of an application where the strength of organics is fully exploited," says Ananth Dodabalapur, an organic electronics pioneer at the University of Texas, Austin. Not that Someya's team is ready to apply their electronic skin to robots yet. Someya notes that the sensors in their network degrade over weeks, something that will need to be stabilized for real world uses. But if his team can solve this and a few other nagging problems, Someya says that the sensors could find a wealth of uses beyond robotics, such as creating a new type of home security system from a network of pressure sensors embedded in carpets. Such applications could hit the market by the end of the decade, Someya believes.
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