MEMS apps expand, but market cools

Other member companies at the MEMS Executive Conference described broad range of consumer devices that use, or will use, MEMS chips for features from buttonless controllers to dead-reckoning navigators.

"Accelerometers are just one type of MEMS chip being integrated into a wide variety of consumer devices," said STMicroelectronics group vice president and general manager Benedetto Vigna. "I predict that by 2012 all cell phones will have accelerometers."

To meet the requirements of diverse consumer devices, ST plans to announce next week that it has created three grades of MEMS accelerometers that trade off low price for high resolution—6-, 8- and12-bit.

Each model will feature a low-power mode that allows the accelerometer to continue functioning even when a cell phone, or other consumer device, goes to sleep. In standby mode power is reduced to less than 1 microamp—300 times less than in normal operating mode. But the new "in-between" low-power mode runs at less than 10 microamps—30-times less than normal—while continuing to supply acceleration data at outputs, albeit at a lower data rate.

ST's accelerometers are already being used in Nintendo's Wii and Apple's iPhone, but its new models, which measure as small as 3-millimeter square, are being targeted for non-safety automotive applications such as car alarms, as well as industrial and health-care devices. ST also claims to be expanding its portfolio of MEMS chips by adding gyroscopes, microphones, and magnetic and pressure sensors.

Freescale Semiconductor demonstrated at the MEMS Executive Congress a new line of three-axis digital accelerometers and a new set of development tools for cell phones, handheld controllers and portable media players. The three-axis accelerometers measure motion in 2G, 4G and 8G ranges, making them a good match for consumer applications such as scrolling, game control and gesture-recognition functions such as "tap to mute."

Because the accelerometers measure motion in all three directions, with their own integrated analog-to-digital converters, they're intended to enable functions not possible with two-axis accelerometers, such as dead reckoning for navigational devices, motion signature detection and pulse detection to control various functions, theft protection and new types of OEM-defined gestures.

The three-axis accelerometers are housed in a thin 3x5x1-mm LGA package that is pin-compatible with existing Freescale MEMS chips, enabling designs already in production to be upgraded without changing board layouts. A new demonstration board and ZigBee-based communications interface, which plugs into a USB port on a PC, can be used to develop designs with up to 16 accelerometer boards.