Python - GPS Bricklet 2.0

This is the description of the Python API bindings for the GPS Bricklet 2.0. General information and technical specifications for the GPS Bricklet 2.0 are summarized in its hardware description.

An installation guide for the Python API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (example_simple.py)

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#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your GPS Bricklet 2.0

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_gps_v2 import BrickletGPSV2

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    gps = BrickletGPSV2(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Get current coordinates
    latitude, ns, longitude, ew = gps.get_coordinates()

    print("Latitude: " + str(latitude/1000000.0) + " °")
    print("N/S: " + ns)
    print("Longitude: " + str(longitude/1000000.0) + " °")
    print("E/W: " + ew)

    raw_input("Press key to exit\n") # Use input() in Python 3
    ipcon.disconnect()

Callback

Download (example_callback.py)

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#!/usr/bin/env python
# -*- coding: utf-8 -*-

HOST = "localhost"
PORT = 4223
UID = "XYZ" # Change XYZ to the UID of your GPS Bricklet 2.0

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_gps_v2 import BrickletGPSV2

# Callback function for coordinates callback
def cb_coordinates(latitude, ns, longitude, ew):
    print("Latitude: " + str(latitude/1000000.0) + " °")
    print("N/S: " + ns)
    print("Longitude: " + str(longitude/1000000.0) + " °")
    print("E/W: " + ew)
    print("")

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    gps = BrickletGPSV2(UID, ipcon) # Create device object

    ipcon.connect(HOST, PORT) # Connect to brickd
    # Don't use device before ipcon is connected

    # Register coordinates callback to function cb_coordinates
    gps.register_callback(gps.CALLBACK_COORDINATES, cb_coordinates)

    # Set period for coordinates callback to 1s (1000ms)
    # Note: The coordinates callback is only called every second
    #       if the coordinates has changed since the last call!
    gps.set_coordinates_callback_period(1000)

    raw_input("Press key to exit\n") # Use input() in Python 3
    ipcon.disconnect()

API

Generally, every method of the Python bindings can throw an tinkerforge.ip_connection.Error exception that has a value and a description property. value can have different values:

  • Error.TIMEOUT = -1
  • Error.ALREADY_CONNECTED = -7
  • Error.NOT_CONNECTED = -8
  • Error.INVALID_PARAMETER = -9
  • Error.NOT_SUPPORTED = -10
  • Error.UNKNOWN_ERROR_CODE = -11
  • Error.STREAM_OUT_OF_SYNC = -12

All methods listed below are thread-safe.

Basic Functions

BrickletGPSV2(uid, ipcon)
Parameters:
  • uid -- string
  • ipcon -- IPConnection

Creates an object with the unique device ID uid:

gps_v2 = BrickletGPSV2("YOUR_DEVICE_UID", ipcon)

This object can then be used after the IP Connection is connected (see examples above).

BrickletGPSV2.get_coordinates()
Return type:(int, chr, int, chr)

Returns the GPS coordinates. Latitude and longitude are given in the DD.dddddd° format, the value 57123468 means 57.123468°. The parameter ns and ew are the cardinal directions for latitude and longitude. Possible values for ns and ew are 'N', 'S', 'E' and 'W' (north, south, east and west).

This data is only valid if there is currently a fix as indicated by get_status().

The returned namedtuple has the variables latitude, ns, longitude and ew.

BrickletGPSV2.get_status()
Return type:(bool, int)

Returns if a fix is currently available as well as the, the number of satellites that are in view.

There is also a green LED on the Bricklet that indicates the fix status.

The returned namedtuple has the variables has_fix and satellites_view.

BrickletGPSV2.get_altitude()
Return type:(int, int)

Returns the current altitude and corresponding geoidal separation.

Both values are given in cm.

This data is only valid if there is currently a fix as indicated by get_status().

The returned namedtuple has the variables altitude and geoidal_separation.

BrickletGPSV2.get_motion()
Return type:(int, int)

Returns the current course and speed. Course is given in hundredths degree and speed is given in hundredths km/h. A course of 0° means the Bricklet is traveling north bound and 90° means it is traveling east bound.

Please note that this only returns useful values if an actual movement is present.

This data is only valid if there is currently a fix as indicated by get_status().

The returned namedtuple has the variables course and speed.

BrickletGPSV2.get_date_time()
Return type:(int, int)

Returns the current date and time. The date is given in the format ddmmyy and the time is given in the format hhmmss.sss. For example, 140713 means 14.05.13 as date and 195923568 means 19:59:23.568 as time.

The returned namedtuple has the variables date and time.

BrickletGPSV2.get_satellite_system_status(satellite_system)
Parameters:satellite_system -- int
Return type:([int, int, ...], int, int, int, int)

Returns the

  • satellite numbers list (up to 12 items)
  • fix value,
  • PDOP value,
  • HDOP value and
  • VDOP value

for a given satellite system. Currently GPS and GLONASS are supported, Galileo is not yet supported.

The GPS and GLONASS satellites have unique numbers and the satellite list gives the numbers of the satellites that are currently utilized. The number 0 is not a valid satellite number and can be ignored in the list.

The following constants are available for this function:

  • BrickletGPSV2.SATELLITE_SYSTEM_GPS = 0
  • BrickletGPSV2.SATELLITE_SYSTEM_GLONASS = 1
  • BrickletGPSV2.SATELLITE_SYSTEM_GALILEO = 2
  • BrickletGPSV2.FIX_NO_FIX = 1
  • BrickletGPSV2.FIX_2D_FIX = 2
  • BrickletGPSV2.FIX_3D_FIX = 3

The returned namedtuple has the variables satellite_numbers, fix, pdop, hdop and vdop.

BrickletGPSV2.get_satellite_status(satellite_system, satellite_number)
Parameters:
  • satellite_system -- int
  • satellite_number -- int
Return type:

(int, int, int)

Returns the current

  • elevation (0° - 90°),
  • azimuth (0° - 359°) and
  • SNR (0dB - 99dB)

for a given satellite and satellite system.

The satellite number here always goes from 1 to 32. For GLONASS it corresponds to the satellites 65-96.

Galileo is not yet supported.

The following constants are available for this function:

  • BrickletGPSV2.SATELLITE_SYSTEM_GPS = 0
  • BrickletGPSV2.SATELLITE_SYSTEM_GLONASS = 1
  • BrickletGPSV2.SATELLITE_SYSTEM_GALILEO = 2

The returned namedtuple has the variables elevation, azimuth and snr.

Advanced Functions

BrickletGPSV2.restart(restart_type)
Parameters:restart_type -- int
Return type:None

Restarts the GPS Bricklet, the following restart types are available:

Value Description
0 Hot start (use all available data in the NV store)
1 Warm start (don't use ephemeris at restart)
2 Cold start (don't use time, position, almanacs and ephemeris at restart)
3 Factory reset (clear all system/user configurations at restart)

The following constants are available for this function:

  • BrickletGPSV2.RESTART_TYPE_HOT_START = 0
  • BrickletGPSV2.RESTART_TYPE_WARM_START = 1
  • BrickletGPSV2.RESTART_TYPE_COLD_START = 2
  • BrickletGPSV2.RESTART_TYPE_FACTORY_RESET = 3
BrickletGPSV2.set_fix_led_config(config)
Parameters:config -- int
Return type:None

Sets the fix LED configuration. By default the LED shows if the Bricklet got a GPS fix yet. If a fix is established the LED turns on. If there is no fix then the LED is turned off.

You can also turn the LED permanently on/off, show a heartbeat or let it blink in sync with the PPS (pulse per second) output of the GPS module.

If the Bricklet is in bootloader mode, the LED is off.

The following constants are available for this function:

  • BrickletGPSV2.FIX_LED_CONFIG_OFF = 0
  • BrickletGPSV2.FIX_LED_CONFIG_ON = 1
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_FIX = 3
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_PPS = 4
BrickletGPSV2.get_fix_led_config()
Return type:int

Returns the configuration as set by set_fix_led_config()

The following constants are available for this function:

  • BrickletGPSV2.FIX_LED_CONFIG_OFF = 0
  • BrickletGPSV2.FIX_LED_CONFIG_ON = 1
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_FIX = 3
  • BrickletGPSV2.FIX_LED_CONFIG_SHOW_PPS = 4
BrickletGPSV2.set_sbas_config(sbas_config)
Parameters:sbas_config -- int
Return type:None

If SBAS is enabled, the position accuracy increases (if SBAS satellites are in view), but the update rate is limited to 5Hz. With SBAS disabled the update rate is increased to 10Hz.

By default SBAS is enabled and the update rate is 5Hz.

The following constants are available for this function:

  • BrickletGPSV2.SBAS_ENABLED = 0
  • BrickletGPSV2.SBAS_DISABLED = 1

New in version 2.0.2 (Plugin).

BrickletGPSV2.get_sbas_config()
Return type:int

Returns the SBAS configuration as set by set_sbas_config()

The following constants are available for this function:

  • BrickletGPSV2.SBAS_ENABLED = 0
  • BrickletGPSV2.SBAS_DISABLED = 1

New in version 2.0.2 (Plugin).

BrickletGPSV2.get_api_version()
Return type:[int, int, int]

Returns the version of the API definition (major, minor, revision) implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

BrickletGPSV2.get_response_expected(function_id)
Parameters:function_id -- int
Return type:bool

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by set_response_expected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

See set_response_expected() for the list of function ID constants available for this function.

BrickletGPSV2.set_response_expected(function_id, response_expected)
Parameters:
  • function_id -- int
  • response_expected -- bool
Return type:

None

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following function ID constants are available for this function:

  • BrickletGPSV2.FUNCTION_RESTART = 6
  • BrickletGPSV2.FUNCTION_SET_FIX_LED_CONFIG = 9
  • BrickletGPSV2.FUNCTION_SET_COORDINATES_CALLBACK_PERIOD = 11
  • BrickletGPSV2.FUNCTION_SET_STATUS_CALLBACK_PERIOD = 13
  • BrickletGPSV2.FUNCTION_SET_ALTITUDE_CALLBACK_PERIOD = 15
  • BrickletGPSV2.FUNCTION_SET_MOTION_CALLBACK_PERIOD = 17
  • BrickletGPSV2.FUNCTION_SET_DATE_TIME_CALLBACK_PERIOD = 19
  • BrickletGPSV2.FUNCTION_SET_SBAS_CONFIG = 27
  • BrickletGPSV2.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletGPSV2.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletGPSV2.FUNCTION_RESET = 243
  • BrickletGPSV2.FUNCTION_WRITE_UID = 248
BrickletGPSV2.set_response_expected_all(response_expected)
Parameters:response_expected -- bool
Return type:None

Changes the response expected flag for all setter and callback configuration functions of this device at once.

BrickletGPSV2.get_spitfp_error_count()
Return type:(int, int, int, int)

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

The returned namedtuple has the variables error_count_ack_checksum, error_count_message_checksum, error_count_frame and error_count_overflow.

BrickletGPSV2.set_bootloader_mode(mode)
Parameters:mode -- int
Return type:int

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

  • BrickletGPSV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletGPSV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletGPSV2.BOOTLOADER_STATUS_OK = 0
  • BrickletGPSV2.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletGPSV2.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletGPSV2.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletGPSV2.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletGPSV2.BOOTLOADER_STATUS_CRC_MISMATCH = 5
BrickletGPSV2.get_bootloader_mode()
Return type:int

Returns the current bootloader mode, see set_bootloader_mode().

The following constants are available for this function:

  • BrickletGPSV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletGPSV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletGPSV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
BrickletGPSV2.set_write_firmware_pointer(pointer)
Parameters:pointer -- int
Return type:None

Sets the firmware pointer for write_firmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

BrickletGPSV2.write_firmware(data)
Parameters:data -- [int, int, ..61x.., int]
Return type:int

Writes 64 Bytes of firmware at the position as written by set_write_firmware_pointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

BrickletGPSV2.set_status_led_config(config)
Parameters:config -- int
Return type:None

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

  • BrickletGPSV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletGPSV2.STATUS_LED_CONFIG_ON = 1
  • BrickletGPSV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletGPSV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletGPSV2.get_status_led_config()
Return type:int

Returns the configuration as set by set_status_led_config()

The following constants are available for this function:

  • BrickletGPSV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletGPSV2.STATUS_LED_CONFIG_ON = 1
  • BrickletGPSV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletGPSV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletGPSV2.get_chip_temperature()
Return type:int

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

BrickletGPSV2.reset()
Return type:None

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

BrickletGPSV2.write_uid(uid)
Parameters:uid -- int
Return type:None

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

BrickletGPSV2.read_uid()
Return type:int

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

BrickletGPSV2.get_identity()
Return type:(str, str, chr, [int, int, int], [int, int, int], int)

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c' or 'd'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

The returned namedtuple has the variables uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

BrickletGPSV2.register_callback(callback_id, function)
Parameters:
  • callback_id -- int
  • function -- callable
Return type:

None

Registers the given function with the given callback_id.

The available callback IDs with corresponding function signatures are listed below.

BrickletGPSV2.set_coordinates_callback_period(period)
Parameters:period -- int
Return type:None

Sets the period in ms with which the CALLBACK_COORDINATES callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_COORDINATES callback is only triggered if the coordinates changed since the last triggering.

The default value is 0.

BrickletGPSV2.get_coordinates_callback_period()
Return type:int

Returns the period as set by set_coordinates_callback_period().

BrickletGPSV2.set_status_callback_period(period)
Parameters:period -- int
Return type:None

Sets the period in ms with which the CALLBACK_STATUS callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_STATUS callback is only triggered if the status changed since the last triggering.

The default value is 0.

BrickletGPSV2.get_status_callback_period()
Return type:int

Returns the period as set by set_status_callback_period().

BrickletGPSV2.set_altitude_callback_period(period)
Parameters:period -- int
Return type:None

Sets the period in ms with which the CALLBACK_ALTITUDE callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_ALTITUDE callback is only triggered if the altitude changed since the last triggering.

The default value is 0.

BrickletGPSV2.get_altitude_callback_period()
Return type:int

Returns the period as set by set_altitude_callback_period().

BrickletGPSV2.set_motion_callback_period(period)
Parameters:period -- int
Return type:None

Sets the period in ms with which the CALLBACK_MOTION callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_MOTION callback is only triggered if the motion changed since the last triggering.

The default value is 0.

BrickletGPSV2.get_motion_callback_period()
Return type:int

Returns the period as set by set_motion_callback_period().

BrickletGPSV2.set_date_time_callback_period(period)
Parameters:period -- int
Return type:None

Sets the period in ms with which the CALLBACK_DATE_TIME callback is triggered periodically. A value of 0 turns the callback off.

The CALLBACK_DATE_TIME callback is only triggered if the date or time changed since the last triggering.

The default value is 0.

BrickletGPSV2.get_date_time_callback_period()
Return type:int

Returns the period as set by set_date_time_callback_period().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the register_callback() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

def my_callback(param):
    print(param)

gps_v2.register_callback(BrickletGPSV2.CALLBACK_EXAMPLE, my_callback)

The available constants with inherent number and type of parameters are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

BrickletGPSV2.CALLBACK_PULSE_PER_SECOND

This callback is triggered precisely once per second, see PPS.

The precision of two subsequent pulses will be skewed because of the latency in the USB/RS485/Ethernet connection. But in the long run this will be very precise. For example a count of 3600 pulses will take exactly 1 hour.

BrickletGPSV2.CALLBACK_COORDINATES
Parameters:
  • latitude -- int
  • ns -- chr
  • longitude -- int
  • ew -- chr

This callback is triggered periodically with the period that is set by set_coordinates_callback_period(). The parameters are the same as for get_coordinates().

The CALLBACK_COORDINATES callback is only triggered if the coordinates changed since the last triggering and if there is currently a fix as indicated by get_status().

BrickletGPSV2.CALLBACK_STATUS
Parameters:
  • has_fix -- bool
  • satellites_view -- int

This callback is triggered periodically with the period that is set by set_status_callback_period(). The parameters are the same as for get_status().

The CALLBACK_STATUS callback is only triggered if the status changed since the last triggering.

BrickletGPSV2.CALLBACK_ALTITUDE
Parameters:
  • altitude -- int
  • geoidal_separation -- int

This callback is triggered periodically with the period that is set by set_altitude_callback_period(). The parameters are the same as for get_altitude().

The CALLBACK_ALTITUDE callback is only triggered if the altitude changed since the last triggering and if there is currently a fix as indicated by get_status().

BrickletGPSV2.CALLBACK_MOTION
Parameters:
  • course -- int
  • speed -- int

This callback is triggered periodically with the period that is set by set_motion_callback_period(). The parameters are the same as for get_motion().

The CALLBACK_MOTION callback is only triggered if the motion changed since the last triggering and if there is currently a fix as indicated by get_status().

BrickletGPSV2.CALLBACK_DATE_TIME
Parameters:
  • date -- int
  • time -- int

This callback is triggered periodically with the period that is set by set_date_time_callback_period(). The parameters are the same as for get_date_time().

The CALLBACK_DATE_TIME callback is only triggered if the date or time changed since the last triggering.

Constants

BrickletGPSV2.DEVICE_IDENTIFIER

This constant is used to identify a GPS Bricklet 2.0.

The get_identity() function and the CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletGPSV2.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a GPS Bricklet 2.0.