Pytrack 2.0 X

This chapter describes the various libraries which are designed for the Pytrack board. This includes details about the various methods and classes available for each of the Pytrack’s sensors.

Note: follow the guide here to be able to use the functions below

3-Axis Accelerometer (LIS2HH12)

Pytrack has a 3-Axis Accelerometer that provides outputs for acceleration as well as roll, pitch and yaw.

Constructors

class LIS2HH12(pytrack = None, sda = ‘P22’, scl = ‘P21’)

Creates a LIS2HH12 object, that will return values for acceleration, roll, pitch and yaw. Constructor must be passed a Pytrack or I2C object to successfully construct.

Methods

LIS2HH12.acceleration()

Read the acceleration from the LIS2HH12. Returns a tuple with the 3 values of acceleration (G).

LIS2HH12.roll()

Read the current roll from the LIS2HH12. Returns a float in degrees in the range -180 to 180.

LIS2HH12.pitch()

Read the current pitch from the LIS2HH12. Returns a float in degrees in the range -90 to 90. Once the board tilts beyond this range the values will repeat. This is due to a lack of yaw measurement, making it not possible to know the exact orientation of the board.

GPS with GLONASS (Quectel L76-L GNSS)

Pytrack has a GPS (with GLONASS) that provides outputs longitude/latitude, speed and other information about the Pytrack’s location.

Constructors

class L76GNSS(pytrack = None, sda = ‘P22’, scl = ‘P21’, timeout = None)

Creates a L76GNSS object, that will return values for longitude and latitude. Constructor must be passed a Pytrack or I2C object to successfully construct. Set the timeout to a time period (in seconds) for the GPS to search for a lock. If a lock is not found by the time the timeout has expired, the coordinates method will return (None, None).

Methods

L76GNSS.coordinates(debug = False)

Read the longitude and latitude from the L76GNSS. Returns a tuple with the longitude and latitude. With debug set to True the output from the GPS is verbose.

L76GNSS.dump_nmea()

Continuously print nmea sentences received from the L76GNSS to the REPL. This is useful if you want to use a graphical tool over UART to visualise GPS reception

L76GNSS.write()

Send commands to the L76GNSS. This function should only be used if advised by Pycom for a specific purpose.

Pytrack class to control supervisor MCU

Constructors

class Pytrack(i2c=None, sda='P22’, scl='P21’)

Initialise I2C communication with the supervisor MCU

Methods

Pytrack.sd_power(enabled=True)

This command allows switching the power supply for the SD card (VCC + PullUP resistors).

Pytrack.sensor_power(enabled=True)

This command allows switching the power supply for the GPS module and any sensors connected through the external 6-pin connector.

Pytrack.gps_standby(enabled=True)

This command allows switching the GPS module into stand-by mode. The GPS module is no longer accessible via I2C in this case.