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    41 

    42 #include "n900accelerometer.h"

    43 #include <QFile>

    44 #include <QDebug>

    45 #include <time.h>

    46 #include <stdio.h>

    47 

    48 char const * const n900accelerometer::id("n900.accelerometer");

    49 char const * const n900accelerometer::filename("/sys/class/i2c-adapter/i2c-3/3-001d/coord");

    50 char const * const n900accelerometer::range("/sys/class/i2c-adapter/i2c-3/3-001d/scale");

    51 char const * const n900accelerometer::rate("/sys/class/i2c-adapter/i2c-3/3-001d/rate");

    52 

    53 n900accelerometer::n900accelerometer(QSensor *sensor)

    54     : n900filebasedsensor(sensor)

    55 {

    56     setReading<QAccelerometerReading>(&m_reading);

    57     // Details derived from the kernel driver

    58     addDataRate(100, 100); // 100Hz

    59     addOutputRange(-22.418, 22.418, 0.17651); // 2G

    60     setDescription(QLatin1String("lis302dl"));

    61 }

    62 

    63 void n900accelerometer::start()

    64 {

    65     if (!QFile::exists(QLatin1String(filename)))

    66         goto error;

    67 

    68     n900filebasedsensor::start();

    69     return;

    70 

    71 error:

    72     sensorStopped();

    73 }

    74 

    75 void n900accelerometer::poll()

    76 {

    77     // Note that this is a rather inefficient way to generate this data.

    78     // Ideally the kernel would scale the hardware's values to m/s^2 for us

    79     // and give us a timestamp along with that data.

    80 

    81     FILE *fd = fopen(filename, "r");

    82     if (!fd) return;

    83     int x, y, z;

    84     int rs = fscanf(fd, "%i %i %i", &x, &y, &z);

    85     fclose(fd);

    86     if (rs != 3) return;

    87 

    88     // Convert from milli-Gs to meters per second per second

    89     // Using 1 G = 9.80665 m/s^2

    90     qreal ax = x * 0.00980665;

    91     qreal ay = y * -0.00980665;

    92     qreal az = z * -0.00980665;

    93 

    94     m_reading.setTimestamp(clock());

    95     m_reading.setX(ax);

    96     m_reading.setY(ay);

    97     m_reading.setZ(az);

    98 

    99     newReadingAvailable();

   100 }

   101