Highly integrated and compact accelerometers have enabled key functions in several portable products. These dual and three-axis units can provide tilt detection, low-level vibration monitoring and higher level monitoring for shock readings. However, each of these applications requires a different accelerometer to address the appropriate g-level measurements. Freescale Semiconductor’s MMA7260Q three-axis accelerometer allows the selection of four g-levels from 1.5 to 6g, so a single accelerometer can address several applications.
Using microelectromechanical system or MEMS technology, the MMA7260Q has X and Y-axes accelerometers formed by a comb structure in one plane and a Z-axis measurement created by a movable plate. These movable elements and a separate signal conditioning circuitry mount in a 16-lead QFN plastic package. Part of the accelerometer circuitry includes two logic inputs that allow the selection of ±1.5, ±2, ±4, or ±6g. An additional gain stage changes the sensitivity from a maximum of 800 to a minimum 200 mV/g (typical) but the tolerance is ±7.5 percent for each range. The programmable aspect allows a microcontroller (MCU) to select the appropriate sensitivity based on the application. As a result, the sensitivity can be changed anytime during the operation of the product. For example, if a measurement on a lower range exceeds the maximum limit for 2 msec, the MCU can automatically adjust the g-range to a higher level and sample the data again.
With MCU selected sensitivity, the accelerometer can switch from a tilt detection or freefall algorithm with a 1.5g setting to a vibration algorithm with the 6g setting. The different sensitivities provide optimized performance in low g applications.
CONTACT: Freescale Semiconductor’s Technical Information CenterTel: 1-800-521-6274
In this new Design News feature, "How it Works," we’re starting off by examining the inner workings of the electronic cigarette. While e-cigarettes seemed like a gimmick just two or three years ago, they’re catching fire -- so to speak. Sales topped $1 billion last year and are set to hit $10 billion by 2017. Cigarette companies are fighting back by buying up e-cigarette manufacturers.
Advertised as the "Most Powerful Tablet Under $100," the Kindle Fire HD 6 was too tempting for the team at iFixit to pass up. Join us to find out if inexpensive means cheap, irreparable, or just down right economical. It's teardown time!
The increased adoption of wireless technology for mission-critical applications has revved up the global market for dynamic electronic general purpose (GP) test equipment. As the link between cloud networks and devices -- smartphones, tablets, and notebooks -- results in more complex devices under test, the demand for radio frequency test equipment is starting to intensify.
Much of the research on lithium-ion batteries is focused on how to make the batteries charge more quickly and last longer than they currently do, work that would significantly improve the experience of mobile device users, as well EV and hybrid car drivers. Researchers in Singapore have come up with what seems like the best solution so far -- a battery that can recharge itself in mere minutes and has a potential lifespan of 20 years.
Some humanoid walking robots are also good at running, balancing, and coordinated movements in group settings. Several of our sports robots have won regional or worldwide acclaim in the RoboCup soccer World Cup, or FIRST Robotics competitions. Others include the world's first hockey-playing robot and a trash-talking Scrabble player.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.