Freescale had already sold millions of MEMS accelerometers as airbag sensors in high-reliability automotive applications before it entered the consumer electronics market a few years ago with accelerometers for hard drives that can lock up their heads when dropped. Now the company is hawking a companion digital barometric pressure sensor that it says will let hard drive makers optimize head flying heights for maximum information density. The digital pressure sensor debuted today (June 2, 2009 ) at the Computex expo in Taipei, Taiwan.

"A hard disk can increase its storage capacity by 200 percent by lowering the slider's flight height from 10 to 7 nanometers," said Wayne Chavez, consumer and industrial operations manager of Freescale's sensor and actuator division. "Using our barometric pressure sensor to measure air density, hard disk drive makers can reliably lower slider flight height to 5 nanometers, which increases storage capacity by four times."

Without a measure of air density, hard drive heads can't run at minimum flight height without failing when barometric pressure changes dramatically, such as onboard an airborne plane.