Lines Matching +full:x +full:- +full:axis
2 * is the definition of +/- values practical or counterintuitive?
13 that produce three-dimensional data in relation to the world where it is
21 of the (x,y,z) triplets, such as different registers to read these coordinates,
28 reference to (x,y,z) orientation, with (x,y) corresponding to these axes on the
29 screen and (z) being depth, the axis perpendicular to the screen.
31 For a screen you probably want (x) coordinates to go from negative on the left
37 reference. This means that the sensor may be flipped upside-down, left-right,
47 Device-to-world examples for some three-dimensional sensor types:
49 - Accelerometers have their world frame of reference toward the center of
50 gravity, usually to the core of the planet. A reading of the (x,y,z) values
55 9.81 m/s^2 upwards along the (z) axis, i.e. out of the screen when the device
57 as the gravity vector is projected 1:1 onto the sensors (z)-axis.
60 is projected onto the (x,y) plane of the display panel.
66 ! x=y=0 / ! x: > 0
67 +--------+ +--------+
69 +--------+ +--------+
77 If the device is tilted to the left, you get a positive x value. If you point
78 its top towards surface, you get a negative y axis.
80 (---------)
81 ! ! y: -g
85 ! ! x: +g <- z: +g -> x: -g
90 (---------)
93 - Magnetometers (compasses) have their world frame of reference relative to the
94 geomagnetic field. The system orientation vis-a-vis the world is defined with
96 ground plane and positive towards magnetic North, (x) is in the ground plane,
97 perpendicular to the North axis and positive towards the East and (z) is
103 (---------)
108 ! ! > North: x > 0
113 (---------)
129 - Gyroscopes detects the movement relative the device itself. The angular
131 device on a flat surface and spin it around the z axis (such as rotating a
133 along the (z) axis if rotated clockwise, and a positive value if rotated
134 counter-clockwise according to the right-hand rule.
137 (---------) y > 0
138 ! ! v---\
141 ! ! <--\
143 ! 1 2 3 ! --/
147 (---------)
154 To achieve this, use the device tree property "mount-matrix" for the sensor.
159 multiplied by this matrix to give the proper vectors values in three-dimensional
173 x' = mxx * x + myx * y + mzx * z
174 y' = mxy * x + myy * y + mzy * z
175 z' = mxz * x + myz * y + mzz * z
185 mount-matrix = "1", "0", "0",
189 The sensor is mounted 30 degrees (Pi/6 radians) tilted along the X axis, so we
190 compensate by performing a -30 degrees rotation around the X axis:
192 mount-matrix = "1", "0", "0",
194 "0", "-0.5", "0.866";
196 The sensor is flipped 180 degrees (Pi radians) around the Z axis, i.e. mounted
197 upside-down:
199 mount-matrix = "0.998", "0.054", "0",
200 "-0.054", "0.998", "0",
203 ???: this does not match "180 degrees" - factors indicate ca. 3 degrees compensation