4 February 2011—Tiny microscale accelerometers revolutionized car air-bag deployment systems in the mid-1990s. Costing a few dollars apiece and just a few millimeters wide, these sensitive microelectromechanical systems (MEMS) devices carved from silicon replaced a bulky, multicomponent deployment system that used to cost more than US $50.
Now researchers at Harvard have fashioned a MEMS force sensor that’s so cheap it could be disposable. It’s made from paper, and each one costs four cents. The team presented the design and experimental results of the device at the IEEE MEMS 2011 conference last week.
The new device emulates the piezoresistive silicon MEMS sensors that are at the heart of many modern accelerometers. Piezoresistance is the change in resistivity when a material is under mechanical stress. Aside from air-bag deployment, MEMS accelerometers are used to monitor vibrations in buildings and bridges, to trigger hard-disk protection in falling laptops, and to sense motion in iPhones and Wii remotes.
Something to incorporate into our plastic monitoring technology to drive the cost even lower?