by Guest Blogger Michelle Kelsey, Freescale Sensor Manager — Accelerometers, the tiny sensors that recognize various motion patterns, were first integrated into a limited number of mobile phones more than 3 years ago. Thanks to consumer appreciation for Apple’s iPhone portrait landscape capability, the availability of Nokia N95’s R&D API to third-party developers and now the Andriod OS with sensor API, motion user interfaces have gone mainstream.
As smart phones have evolved with increasing functionality, a transition has been occurring within the accelerometers as well. More and more embedded functions are being added into the accelerometer, allowing significant benefits to the mobile system. Freescale released the MMA8450Q 12-bit accelerometer today, which is designed to help system engineers develop smarter smart phones with the following features:
- Orientation detection that allows for custom response depending on the mode, faster response time (i.e. browsing the web verses dialing a phone number) and higher reliability by considering environmental effects (i.e. in a car or walking while dialing)
- Acceleration data buffers to ensure gesture recognition can be achieved with preserving data if it is not able to be processed right away
- Auto-sleep detection that can tell the system processor to go to sleep to significantly save system power
- Auto-wake detection that allows the accelerometer to wake-up the system by a shake, tap, flip or any combination of multiple configurable gestures
- Tap and double tap detection for controlling functions without having to wait for a display to appear and to find the location of the touch screen buttons
- Shake detection to eliminate the need for finding the small side buttons for controlling volume or for sliding through a display or menu
- 12-bit acceleration data for more complex motion gesture detection for control and for more intense mobile games
- Configurable output data rates with significant savings in power (ie. The MMA8450Q can achieve 50Hz ODR with only 27uA current consumption)
I recently transitioned from a mobile phone to a smart phone. You can be sure that I’m interested in seeing the usage of the accelerometer for power savings to reduce the need of daily battery charging. In addition, I’m looking forward to seeing more motion gesture detection added so that I can easily and quickly control the growing number of smart phone features without having to stare at the display for the right virtual button to push.
It will ultimately be up to the system designer to incorporate sensor interrupts to the processor, the OS designers for extending the existing sensor framework for the increasing embedded sensor functions, and the applications developers for utilizing the embedded functions.
I personally have tried a few basic motion apps, but would like to hear if you have found some that are entertaining or some that could be improved with more motion functionality or some of the new MMA8450Q’s embedded functionality.