2014/10/15 下午 10:09:55

iphone Programming Glossary: gravity

How to detect iPhone movement in space using accelerometer?

http://stackoverflow.com/questions/2674717/how-to-detect-iphone-movement-in-space-using-accelerometer

Here is how I proceed admiting the device is hold verticaly 1 I have my default x y and z values. 2 I extract the gravity vector from this data using a low pass filter. 3 I substract the normalized gravity vector from each x y and z and get the.. x y and z values. 2 I extract the gravity vector from this data using a low pass filter. 3 I substract the normalized gravity vector from each x y and z and get the movement acceleration. 4 Then I integrate this acceleration value with respect to.. NSDate now NSDate date if previousDate nil interval now timeIntervalSinceDate previousDate previousDate now Isolating gravity vector gravity.x currentAcceleration.x kFileringFactor gravity.x 1.0 kFileringFactor gravity.y currentAcceleration.y kFileringFactor..

Detecting Acceleration in a car (iPhone Accelerometer)

http://stackoverflow.com/questions/2733249/detecting-acceleration-in-a-car-iphone-accelerometer

force on the z axis but this obviously lead to problems unless the iPhone was oriented directly upright because of gravity. Some trigonometry later and I had managed to work gravity out of the equation so that the car was actually being read very.. unless the iPhone was oriented directly upright because of gravity. Some trigonometry later and I had managed to work gravity out of the equation so that the car was actually being read very very well by the iPhone. Until I hit a slope. As soon as.. been trying to implement for longer than I would like to admit. It's steps are as follows 1 During calibration measure gravity as a vector instead of a size. Store that vector. 2 When the car initially moves forward take the vector of motion and subtract..

Compensating compass lag with the gyroscope on iPhone 4

http://stackoverflow.com/questions/4212988/compensating-compass-lag-with-the-gyroscope-on-iphone-4

nor roll for my purposes yaw ranges from 0 to PI when the phone is pointing downwards as indicated by deviceMotion.gravity.z and swinging counterclockwise and 0 to PI when swung clockwise when the device is pointing upwards yaw ranges from PI.. from 0 to 360 and increase when the device is swung clockwise though I am still having trouble when deviceManager.gravity.z is around 0 the yaw value freaks out at this gravity.z value . It seems to me that I could synchronize the horizontal.. clockwise though I am still having trouble when deviceManager.gravity.z is around 0 the yaw value freaks out at this gravity.z value . It seems to me that I could synchronize the horizontal and magneticHeading values using a calculated horizontal..