News tagged with accelerometers
Clinical measurement of physical activity appears to be an independent predictor of whether or not patients with chronic obstructive pulmonary disease (COPD) will end up being hospitalized, according to a new study conducted ...
Diseases, Conditions, Syndromes May 21, 2013 | not rated yet | 0
A new 3-D motion detection system could help identify baseball pitchers who are at risk for shoulder injuries, according to a new study. The system can be used on the field, and requires only a laptop computer. Other systems ...
Surgery Apr 23, 2013 | not rated yet | 0
Researchers have generated new insights into the ways in which physical activity affects how much estrogen is broken down and secreted in the urine of postmenopausal women. These findings enhance understanding of the potential ...
Cancer Apr 10, 2013 | not rated yet | 0
(HealthDay)—Women who struggle with chronic obesity end up engaging in less and less routine physical activity, new research shows, confirming what may seem obvious to some.
Overweight and Obesity Apr 06, 2013 | 3 / 5 (2) | 1
(Medical Xpress)—Physical activity and its relation to obesity has been studied for decades by researchers; however, almost no one has studied the reverse – obesity's effect on physical activity.
Overweight and Obesity Mar 28, 2013 | 4.5 / 5 (2) | 0
Despite overwhelming evidence about the benefits of physical activity for children, most American youngsters are not meeting the federal recommendation of 60 minutes a day.
Health Mar 13, 2013 | not rated yet | 0
Sitting less and moving about more could be more important than vigorous exercise to reduce your risk of type 2 diabetes
New research led at the University of Leicester reveals that individuals at high risk of developing type 2 diabetes would benefit from being told to sit less and move around more often- rather than simply exercising regularly. ...
Diabetes Feb 27, 2013 | 4.5 / 5 (2) | 0
Understanding the relationships between lifestyle behaviors and health outcomes can be enhanced by the use of wearable cameras, concludes a collection of studies in a special theme issue of the American Jo ...
Health Feb 05, 2013 | 1 / 5 (1) | 0
(Medical Xpress)—Physical activity rather than food has the biggest impact on children's weight according to new data from the Lifestyle of our Kids (LOOK) longitudinal study.
Health Nov 22, 2012 | not rated yet | 0
(HealthDay)—The use of actigraphy to record movement as an objective surrogate for eczema activity is of limited use, according to a study published in the November issue of the British Journal of Dermatology.
Diseases, Conditions, Syndromes Nov 05, 2012 | not rated yet | 0
Researchers in Georgia Tech's Center for Behavior Imaging have developed two new technological tools that automatically measure relevant behaviors of children, and promise to have significant impact on the ...
Autism spectrum disorders Sep 25, 2012 | 5 / 5 (1) | 0
Children who spend more than three-quarters of their time engaging in sedentary behaviour, such as watching TV and sitting at computers, have up to nine times poorer motor coordination than their more active peers, reveals ...
Health Aug 15, 2012 | not rated yet | 0
(Medical Xpress) -- Menopausal women who exercise may experience fewer hot flashes in the 24 hours following physical activity, according to health researchers.
Health Jun 27, 2012 | not rated yet | 0
The University of Notre Dame's annual Bengal Bouts student boxing tournament's longtime mantra is "Strong Bodies Fight that Weak Bodies May Be Nourished."
Medical research Mar 02, 2012 | not rated yet | 0
(HealthDay) -- Apparently there's no guarantee that your kids will mend their couch-potato ways if you give them a fitness video game.
Health Feb 27, 2012 | 3 / 5 (2) | 0
An accelerometer is a device that measures proper acceleration, also called the four-acceleration. This is not necessarily the same as the coordinate acceleration (change of velocity of the device in three-dimensional space), but is rather the type of acceleration associated with the phenomenon of weight experienced by a test mass that resides in the frame of reference of the accelerometer device. For an example of where these types of acceleration differ, an accelerometer will measure a value when sitting on the ground, because masses there have weights, even though they do not change velocity. However, an accelerometer in gravitational free fall toward the center of the Earth will measure a value of zero because, even though its speed is increasing, it is in a frame of reference in which it is weightless.
An accelerometer thus measures weight per unit of (test) mass, a quantity of acceleration also known as specific force, or g-force (although it is not a force, and these quantities are badly-named). Another way of stating this is that by measuring weight, an accelerometer measures the acceleration of the free-fall reference frame (inertial reference frame) relative to itself (the accelerometer). This measurable acceleration is not the ordinary acceleration of Newton (in three dimensions), but rather four-acceleration, which is acceleration away from a geodesic path in four-dimensional space-time.
Most accelerometers do not display the value they measure, but supply it to other devices. Real accelerometers also have practical limitations in how quickly they respond to changes in acceleration, and cannot respond to changes above a certain frequency of change.
Single- and multi-axis models of accelerometer are available to detect magnitude and direction of the proper acceleration (or g-force), as a vector quantity, and can be used to sense orientation (because direction of weight changes), coordinate acceleration (so long as it produces g-force or a change in g-force), vibration, shock, and falling (a case where the proper acceleration changes, since it tends toward zero). Micromachined accelerometers are increasingly present in portable electronic devices and video game controllers, to detect the position of the device or provide for game input.
Pairs of accelerometers extended over a region of space can be used to detect differences (gradients) in the proper accelerations of frames of references associated with those points. These devices are called gravity gradiometers, as they measure gradients in the gravitational field. Such pairs of accelerometers in theory may also be able to detect gravitational waves.
For more information about Accelerometer, read the full article at
This text uses material from Wikipedia and is available under the GNU Free Documentation License.