Developments to Watch
A MICROMACHINE THAT CUTS AIR-BAG COSTS
Researchers in a few university, corporate, and government labs have built the first rudimentary "micromachines," devices with moving parts such as microscopic gears etched from silicon. Now, Analog Devices Inc., a Norwood (Mass.) chipmaker, has passed the experimental stage and put the world's first micromachine on the market.
The company designed an air-bag trigger with a comb-like gauge machined from pure silicon. The gauge works by measuring minute changes in an electrical current that holds the 48 microscopic teeth of the comb rigid. The force of the collision acting on the teeth causes the current to change, triggering the air bag.
By making its sensors in a high-volume process, Analog Devices expects to sell the chips for just $5 each, a fraction of the $20 to $50 cost of mechanical switches now used in auto air-bag systems. The first cars to employ the microchip triggers could appear in 1994. Analog Devices is working on other micromachined sensors for controlling automobile suspensions.EDITED BY PAMELA J. BLACK