core-motion

I am using the iOS core motion framework to detect if the device is tilted forward or backwards. See image for details: http://i.stack.imgur.com/2Ojw5.jpg Using the pitch value a can detect this movement but I can not distinguish between forward AND backward. More details: I try to detect if there is a movement (tilting forward and backward) in either the forward area OR backward area (see updated sketch). The problem with the pitch is that it starts with a value of about 1.6 if the device is in an upright position. And the value decreases the same when I am tilting it towards a horizontal

I'm trying to detect the movement (to the right or left) performed by users. We assume that the user starts with his arm extended in front of him and then moves his arm to the right or to the left (about 90 degrees off center). I've integrated CMMotionManager and want to understand detecting direction via startAccelerometerUpdatesToQueue and startDeviceMotionUpdatesToQueue methods. Can anyone suggest how to implement this logic on an iPhone and then on an Apple Watch? Apple provides watchOS 3 SwingWatch sample code demonstrating how to use CMMotionManager() and startDeviceMotionUpdates(to:) to

i'm trying to run Madgwick's sensor fusion algorithm on iOS. Since the code is open source i already included it in my project and call the methods with the provided sensor values. But it seems, that the algorithm expects the sensor measurements in a different coordinate system. The Apple CoreMotion Sensor System is given on the right side, Madgewick's on the left. Here is the picture of the different coordinate systems . Both systems follow the right hand rule. For me it seems like there is a 90 degree rotation around the z axis. But this didn't work. I also tried to flip x and y (and invert

I want to compute rate of change of orientation of the iPhone along y axis. 1. Initially i need to define the reference as y axis, 2. Then measure the rate of change of orientation(angular measurement) from the defined reference. Does CMAttitude provides a reliable angular measurements to implement this? Or Can i use rotational matrix or integrate gyroscope data(I implement this method, but it's not going to work due to the drift of the gyroscope). So please suggest me a reliable method to get this done? Thank you in advance! First, just to clarify: Rotation rates are not measured "from" any

When push method is used to get accelerometer/gyroscope/device motion data, unfortunately the gyroscope and the device motion maximum frequency cannot exceed 72Hz on average (in fact the data is not periodic at all either). Even worse, if only the gyroscope data is recorded (without starting device motion update service: i.e. using only [motionManager startGyroUpdatesToQueue:opQ withHandler:gyroHandler]), then the gyroscope data frequency drops to 52Hz on average. Has anyone tried to obtain gyroscope data at 100Hz using pull method? Can we reach the maximum 100Hz throughput with the "pull

I'm getting the acceleration data using the -[CMDeviceMotion userAcceleration] I've noticed one interesting thing: I always get a small bias on the Z axis. It is about 0.0155 (with variance of 0.002). While on other axes the average values are near 0. I'm testing this with iPod Touch 4G (and it is just laying on the table during testing). The question is: where this bias is from and is it device specific? I noticed similar values although CoreMotion tries to eliminate bias. If you rotate your device so that x (or y) is parallele to gravity you will probably see the bias in x direction. Using