48 |
48 |
49 /*! |
49 /*! |
50 \class QMagnetometerReading |
50 \class QMagnetometerReading |
51 \ingroup sensors_reading |
51 \ingroup sensors_reading |
52 |
52 |
53 \preliminary |
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54 \brief The QMagnetometerReading class represents one reading from the |
53 \brief The QMagnetometerReading class represents one reading from the |
55 magnetometer. |
54 magnetometer. |
56 |
55 |
57 \section2 QMagnetometerReading Units |
56 \section2 QMagnetometerReading Units |
58 The magnetometer returns magnetic flux density values along 3 axes. |
57 The magnetometer returns magnetic flux density values along 3 axes. |
59 The scale of the values is teslas. The axes are arranged as follows. |
58 The scale of the values is teslas. The axes are arranged as follows. |
60 |
59 |
61 \code |
60 \image sensors-coordinates2.jpg |
62 +z |
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63 | |
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64 | +y |
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65 | / |
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66 |----/---- |
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67 /| NOKIA /| |
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68 //|--/--- / | |
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69 // | / // / |
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70 // |/ // / |
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71 // '--------------- +x |
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72 // // / |
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73 // // / |
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74 /---------/ / |
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75 / O / / |
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76 / / / |
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77 ---------- / |
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78 |_________!/ |
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79 \endcode |
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80 |
61 |
81 The magnetometer can report on either raw magnetic flux values or geomagnetic flux values. |
62 The magnetometer can report on either raw magnetic flux values or geomagnetic flux values. |
82 By default it returns raw magnetic flux values. The QMagnetometer::returnGeoValues property |
63 By default it returns raw magnetic flux values. The QMagnetometer::returnGeoValues property |
83 must be set to return geomagnetic flux values. |
64 must be set to return geomagnetic flux values. |
84 |
65 |
85 The primary difference between raw and geomagnetic values is that extra processing |
66 The primary difference between raw and geomagnetic values is that extra processing |
86 is done to eliminate local magnetic interference from the geomagnetic values so they |
67 is done to eliminate local magnetic interference from the geomagnetic values so they |
87 represent only the effect of the Earth's magnetic field. This process is not perfect |
68 represent only the effect of the Earth's magnetic field. This process is not perfect |
88 and the accuracy of each reading may change. |
69 and the accuracy of each reading may change. |
89 |
70 |
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71 The image below shows the difference between geomagnetic (on the left) and raw (on the right) |
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72 readings for a phone that is being subjected to magnetic interference. |
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73 |
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74 \image sensors-geo-vs-raw-magnetism.jpg |
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75 |
90 The accuracy of each reading is measured as a number from 0 to 1. |
76 The accuracy of each reading is measured as a number from 0 to 1. |
91 A value of 1 is the highest level that the device can support and 0 is |
77 A value of 1 is the highest level that the device can support and 0 is |
92 the worst. |
78 the worst. |
93 */ |
79 */ |
94 |
80 |
183 |
169 |
184 /*! |
170 /*! |
185 \class QMagnetometerFilter |
171 \class QMagnetometerFilter |
186 \ingroup sensors_filter |
172 \ingroup sensors_filter |
187 |
173 |
188 \preliminary |
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189 \brief The QMagnetometerFilter class is a convenience wrapper around QSensorFilter. |
174 \brief The QMagnetometerFilter class is a convenience wrapper around QSensorFilter. |
190 |
175 |
191 The only difference is that the filter() method features a pointer to QMagnetometerReading |
176 The only difference is that the filter() method features a pointer to QMagnetometerReading |
192 instead of QSensorReading. |
177 instead of QSensorReading. |
193 */ |
178 */ |