Researchers at Stanford University have built one of the most complex circuits from carbon nanotubes yet. They showed off a simple hand-shaking robot with a sensor-interface circuit last week at the International Solid-State Circuits Conference in San Francisco.
As the silicon transistors inside today’s computers reach their physical limits, the semiconductor industry is eyeing alternatives, and one of the most promising is carbon nanotubes. Tiny transistors made from these nanomaterials are faster and more energy efficient than silicon ones, and computer models predict that carbon nanotube processors could be an order of magnitude less power hungry. But it’s proved difficult to turn individual transistors into complex working circuits (see “How to Build a Nano-Computer”).
The demonstration carbon nanotube circuit converts an analog signal from a capacitor—the same type of sensor found in many touch screens—into a digital signal that’s comprehensible by a microprocessor. The Stanford researchers rigged a wooden mannequin hand with the capacitive switch in its palm. When someone graspsed the hand, turning on the switch, the nanotube circuit sent its signal to the computer, which activated a motor on the robot hand, moving it up and down to shake the person’s hand.