A process for fetching data from sensors using the I2C protocol.
See the help documentation with the command: use fetcher.
The output of fetcher looks like:
Time: 1295 ms
Temperature: 25.02 C
Pressure: 99.94 kPa
...Sensor data output can either be printed in plain-text, or it can be read from the named message queue
fetcher/sensors.
Messages on the message queue start with a one-byte type specifier which is one of the following:
/** Describes possible data types that fetcher is capable of producing. */
typedef enum {
TAG_TEMPERATURE = 0, /**< Temperature in degrees Celsius */
TAG_PRESSURE = 1, /**< Pressure in kilo Pascals */
TAG_HUMIDITY = 2, /**< Humidity in % relative humidity */
TAG_TIME = 3, /**< Time in milliseconds */
TAG_ALTITUDE_SEA = 4, /**< Altitude above sea level in meters */
TAG_ALTITUDE_REL = 5, /**< Altitude above launch height in meters */
TAG_ANGULAR_VEL = 6, /**< Angular velocity in degrees per second */
TAG_LINEAR_ACCEL_REL = 7, /**< Relative linear acceleration in meters per second squared */
TAG_LINEAR_ACCEL_ABS = 8, /**< Absolute linear acceleration in meters per second squared */
} SensorTag;Followed by data representing the measurement.
Temperature, pressure, humidity and altitude are floats.
Time is a 32 bit integer.
Linear acceleration and angular velocity are 3D vectors (vec3d_t) of 3 floats.
In order for fetcher to recognize the sensors on the board, the EEPROM must encode the ID in this format:
CU InSpace <board name>
REV <x>: <manufacture date>
<sensor 1 id> <address>
<sensor 2 id> <address> <address2>
Fields:
<board name>: The name of the board. Ex:Sensor boardREV <x>: The revision of the board. Ex:REV B<sensor id>: The identifier of the sensor. Ex:MS5611<address>: The 7 bit I2C address of the sensor in hexadecimal (without the leading 0x). Ex:77- It is possible to have more than one address per sensor type for boards with duplicates