Microsensors without microfabrication
Miniature motion sensors are everywhere these days, detecting the orientation of cell phones, deploying air bags in cars and measuring stresses in buildings and mechanical systems. But manufacturing the sensors’ tiny moving parts requires the same high-tech, billion-dollar facilities that churn out computer chips.Researchers at MIT’s Center for Bits and Atoms (CBA) have now built a motion sensor that consists of a tiny metal bead suspended in what the center’s director, Neil Gershenfeld, describes as “a hole drilled in a circuit board.” A fluctuating electric field holds the bead aloft, in a tight orbit, and disturbances of the orbit indicate the sensor’s direction of motion. Gershenfeld believes that the sensor opens the door to a new class of miniaturized devices that exploit the dynamics of simple physical systems instead of the mechanical interactions of precisely micromachined parts. Such “microdynamical” devices, Gershenfeld says, could enable cheaper, simpler, more responsive sensors for...