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39
40#include "genericalssensor.h"
41#include <QDebug>
42
43char const * const genericalssensor::id("generic.als");
44
45genericalssensor::genericalssensor(QSensor *sensor)
46 : QSensorBackend(sensor)
47{
48 lightSensor = new QLightSensor(this);
49 lightSensor->addFilter(filter: this);
50 lightSensor->connectToBackend();
51
52 setReading<QAmbientLightReading>(&m_reading);
53 setDataRates(lightSensor);
54}
55
56void genericalssensor::start()
57{
58 lightSensor->setDataRate(sensor()->dataRate());
59 lightSensor->setAlwaysOn(sensor()->isAlwaysOn());
60 lightSensor->start();
61 if (!lightSensor->isActive())
62 sensorStopped();
63 if (lightSensor->isBusy())
64 sensorBusy();
65}
66
67void genericalssensor::stop()
68{
69 lightSensor->stop();
70}
71
72struct lux_limit {
73 int min;
74 int max;
75};
76
77// Defines the min and max lux values that a given level has.
78// These are used to add histeresis to the sensor.
79// If the previous level is below a level, the lux must be at or above the minimum.
80// If the previous level is above a level, the lux muyt be at or below the maximum.
81static lux_limit limits[] = {
82 { .min: 0, .max: 0 }, // Undefined (not used)
83 { .min: 0, .max: 5 }, // Dark
84 { .min: 10, .max: 50 }, // Twilight
85 { .min: 100, .max: 200 }, // Light
86 { .min: 500, .max: 2000 }, // Bright
87 { .min: 5000, .max: 0 } // Sunny
88};
89
90#if 0
91// Used for debugging
92static QString light_level(int level)
93{
94 switch (level) {
95 case 1:
96 return QLatin1String("Dark");
97 case 2:
98 return QLatin1String("Twilight");
99 case 3:
100 return QLatin1String("Light");
101 case 4:
102 return QLatin1String("Bright");
103 case 5:
104 return QLatin1String("Sunny");
105 default:
106 return QLatin1String("Undefined");
107 }
108}
109#endif
110
111bool genericalssensor::filter(QLightReading *reading)
112{
113 // It's unweildly dealing with these constants so make some
114 // local aliases that are shorter. This makes the code below
115 // much easier to read.
116 enum {
117 Undefined = QAmbientLightReading::Undefined,
118 Dark = QAmbientLightReading::Dark,
119 Twilight = QAmbientLightReading::Twilight,
120 Light = QAmbientLightReading::Light,
121 Bright = QAmbientLightReading::Bright,
122 Sunny = QAmbientLightReading::Sunny
123 };
124
125 int lightLevel = m_reading.lightLevel();
126 qreal lux = reading->lux();
127
128 // Check for change direction to allow for histeresis
129 if (lightLevel < Sunny && lux >= limits[Sunny ].min) lightLevel = Sunny;
130 else if (lightLevel < Bright && lux >= limits[Bright ].min) lightLevel = Bright;
131 else if (lightLevel < Light && lux >= limits[Light ].min) lightLevel = Light;
132 else if (lightLevel < Twilight && lux >= limits[Twilight].min) lightLevel = Twilight;
133 else if (lightLevel < Dark && lux >= limits[Dark ].min) lightLevel = Dark;
134 else if (lightLevel > Dark && lux <= limits[Dark ].max) lightLevel = Dark;
135 else if (lightLevel > Twilight && lux <= limits[Twilight].max) lightLevel = Twilight;
136 else if (lightLevel > Light && lux <= limits[Light ].max) lightLevel = Light;
137 else if (lightLevel > Bright && lux <= limits[Bright ].max) lightLevel = Bright;
138
139 //qDebug() << "lightLevel" << light_level(lightLevel) << "lux" << lux;
140
141 if (static_cast<int>(m_reading.lightLevel()) != lightLevel || m_reading.timestamp() == 0) {
142 m_reading.setTimestamp(reading->timestamp());
143 m_reading.setLightLevel(static_cast<QAmbientLightReading::LightLevel>(lightLevel));
144
145 newReadingAvailable();
146 }
147
148 return false;
149}
150
151

source code of qtsensors/src/plugins/sensors/generic/genericalssensor.cpp