MQTT - GPS Bricklet 2.0

This is the description of the MQTT 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 MQTT API bindings is part of their general description.

Examples

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

Simple

Download (example-simple.txt)

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# Change XYZ to the UID of your GPS Bricklet 2.0

setup:
    # Get current coordinates
    subscribe to tinkerforge/response/gps_v2_bricklet/XYZ/get_coordinates
    publish '' to tinkerforge/request/gps_v2_bricklet/XYZ/get_coordinates

Callback

Download (example-callback.txt)

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# Change XYZ to the UID of your GPS Bricklet 2.0

setup:
    # Handle incoming coordinates callbacks
    subscribe to tinkerforge/callback/gps_v2_bricklet/XYZ/coordinates
    publish '{"register": true}' to tinkerforge/register/gps_v2_bricklet/XYZ/coordinates # Register coordinates callback
    
    # 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!
    publish '{"period": 1000}' to tinkerforge/request/gps_v2_bricklet/XYZ/set_coordinates_callback_period

API

All published payloads to and from the MQTT bindings are in JSON format.

If an error occures, the bindings publish a JSON object containing the error message as attribute "_ERROR". It is published on the corresponding response topic: .../response/... for .../request/... and .../callback/... for .../register/....

Basic Functions

request/gps_v2_bricklet/<UID>/get_coordinates
Response payload:
  • latitude -- int
  • ns -- char
  • longitude -- int
  • ew -- char

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 request/gps_v2_bricklet/<UID>/get_status.

request/gps_v2_bricklet/<UID>/get_status
Response payload:
  • has_fix -- bool
  • satellites_view -- 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.

request/gps_v2_bricklet/<UID>/get_altitude
Response payload:
  • altitude -- int
  • geoidal_separation -- 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 request/gps_v2_bricklet/<UID>/get_status.

request/gps_v2_bricklet/<UID>/get_motion
Response payload:
  • course -- int
  • speed -- 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 request/gps_v2_bricklet/<UID>/get_status.

request/gps_v2_bricklet/<UID>/get_date_time
Response payload:
  • date -- int
  • time -- 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 14.07.13 as date and 195923568 means 19:59:23.568 as time.

request/gps_v2_bricklet/<UID>/get_satellite_system_status
Request payload:
  • satellite_system -- int (has symbols)
Response payload:
  • satellite_numbers -- [int,...]
  • fix -- int (has symbols)
  • pdop -- int
  • hdop -- int
  • vdop -- 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 symbols are available for this function:

for satellite_system:

  • "GPS" = 0
  • "GLONASS" = 1
  • "Galileo" = 2

for fix:

  • "NoFix" = 1
  • "2DFix" = 2
  • "3DFix" = 3
request/gps_v2_bricklet/<UID>/get_satellite_status
Request payload:
  • satellite_system -- int (has symbols)
  • satellite_number -- int
Response payload:
  • elevation -- int
  • azimuth -- int
  • snr -- 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 symbols are available for this function:

for satellite_system:

  • "GPS" = 0
  • "GLONASS" = 1
  • "Galileo" = 2

Advanced Functions

request/gps_v2_bricklet/<UID>/restart
Request payload:
  • restart_type -- int (has symbols)

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 symbols are available for this function:

for restart_type:

  • "HotStart" = 0
  • "WarmStart" = 1
  • "ColdStart" = 2
  • "FactoryReset" = 3
request/gps_v2_bricklet/<UID>/set_fix_led_config
Request payload:
  • config -- int (has symbols)

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 symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowFix" = 3
  • "ShowPPS" = 4
request/gps_v2_bricklet/<UID>/get_fix_led_config
Response payload:
  • config -- int (has symbols)

Returns the configuration as set by request/gps_v2_bricklet/<UID>/set_fix_led_config

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowFix" = 3
  • "ShowPPS" = 4
request/gps_v2_bricklet/<UID>/set_sbas_config
Request payload:
  • sbas_config -- int (has symbols)

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 symbols are available for this function:

for sbas_config:

  • "Enabled" = 0
  • "Disabled" = 1

New in version 2.0.2 (Plugin).

request/gps_v2_bricklet/<UID>/get_sbas_config
Response payload:
  • sbas_config -- int (has symbols)

Returns the SBAS configuration as set by request/gps_v2_bricklet/<UID>/set_sbas_config

The following symbols are available for this function:

for sbas_config:

  • "Enabled" = 0
  • "Disabled" = 1

New in version 2.0.2 (Plugin).

request/gps_v2_bricklet/<UID>/get_spitfp_error_count
Response payload:
  • error_count_ack_checksum -- int
  • error_count_message_checksum -- int
  • error_count_frame -- int
  • error_count_overflow -- 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.

request/gps_v2_bricklet/<UID>/set_bootloader_mode
Request payload:
  • mode -- int (has symbols)
Response payload:
  • status -- int (has symbols)

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 symbols are available for this function:

for mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4

for status:

  • "OK" = 0
  • "InvalidMode" = 1
  • "NoChange" = 2
  • "EntryFunctionNotPresent" = 3
  • "DeviceIdentifierIncorrect" = 4
  • "CRCMismatch" = 5
request/gps_v2_bricklet/<UID>/get_bootloader_mode
Response payload:
  • mode -- int (has symbols)

Returns the current bootloader mode, see request/gps_v2_bricklet/<UID>/set_bootloader_mode.

The following symbols are available for this function:

for mode:

  • "Bootloader" = 0
  • "Firmware" = 1
  • "BootloaderWaitForReboot" = 2
  • "FirmwareWaitForReboot" = 3
  • "FirmwareWaitForEraseAndReboot" = 4
request/gps_v2_bricklet/<UID>/set_write_firmware_pointer
Request payload:
  • pointer -- int

Sets the firmware pointer for request/gps_v2_bricklet/<UID>/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.

request/gps_v2_bricklet/<UID>/write_firmware
Request payload:
  • data -- [int,... (x64)]
Response payload:
  • status -- int

Writes 64 Bytes of firmware at the position as written by request/gps_v2_bricklet/<UID>/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.

request/gps_v2_bricklet/<UID>/set_status_led_config
Request payload:
  • config -- int (has symbols)

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 symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/gps_v2_bricklet/<UID>/get_status_led_config
Response payload:
  • config -- int (has symbols)

Returns the configuration as set by request/gps_v2_bricklet/<UID>/set_status_led_config

The following symbols are available for this function:

for config:

  • "Off" = 0
  • "On" = 1
  • "ShowHeartbeat" = 2
  • "ShowStatus" = 3
request/gps_v2_bricklet/<UID>/get_chip_temperature
Response payload:
  • temperature -- 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.

request/gps_v2_bricklet/<UID>/reset

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!

request/gps_v2_bricklet/<UID>/write_uid
Request payload:
  • uid -- int

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.

request/gps_v2_bricklet/<UID>/read_uid
Response payload:
  • uid -- int

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

request/gps_v2_bricklet/<UID>/get_identity
Response payload:
  • uid -- string
  • connected_uid -- string
  • position -- char
  • hardware_version -- [int,int,int]
  • firmware_version -- [int,int,int]
  • device_identifier -- int (has symbols)
  • _display_name -- string

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. If symbolic output is not disabled, the device identifier is mapped to the corresponding name in the format used in topics.

The display name contains the GPS 2.0's name in a human readable form.

Callback Configuration Functions

request/gps_v2_bricklet/<UID>/set_coordinates_callback_period
Request payload:
  • period -- int

Sets the period in ms with which the register/gps_v2_bricklet/<UID>/coordinates callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v2_bricklet/<UID>/coordinates callback is only triggered if the coordinates changed since the last triggering.

The default value is 0.

request/gps_v2_bricklet/<UID>/get_coordinates_callback_period
Response payload:
  • period -- int

Returns the period as set by request/gps_v2_bricklet/<UID>/set_coordinates_callback_period.

request/gps_v2_bricklet/<UID>/set_status_callback_period
Request payload:
  • period -- int

Sets the period in ms with which the register/gps_v2_bricklet/<UID>/status callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v2_bricklet/<UID>/status callback is only triggered if the status changed since the last triggering.

The default value is 0.

request/gps_v2_bricklet/<UID>/get_status_callback_period
Response payload:
  • period -- int

Returns the period as set by request/gps_v2_bricklet/<UID>/set_status_callback_period.

request/gps_v2_bricklet/<UID>/set_altitude_callback_period
Request payload:
  • period -- int

Sets the period in ms with which the register/gps_v2_bricklet/<UID>/altitude callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v2_bricklet/<UID>/altitude callback is only triggered if the altitude changed since the last triggering.

The default value is 0.

request/gps_v2_bricklet/<UID>/get_altitude_callback_period
Response payload:
  • period -- int

Returns the period as set by request/gps_v2_bricklet/<UID>/set_altitude_callback_period.

request/gps_v2_bricklet/<UID>/set_motion_callback_period
Request payload:
  • period -- int

Sets the period in ms with which the register/gps_v2_bricklet/<UID>/motion callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v2_bricklet/<UID>/motion callback is only triggered if the motion changed since the last triggering.

The default value is 0.

request/gps_v2_bricklet/<UID>/get_motion_callback_period
Response payload:
  • period -- int

Returns the period as set by request/gps_v2_bricklet/<UID>/set_motion_callback_period.

request/gps_v2_bricklet/<UID>/set_date_time_callback_period
Request payload:
  • period -- int

Sets the period in ms with which the register/gps_v2_bricklet/<UID>/date_time callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v2_bricklet/<UID>/date_time callback is only triggered if the date or time changed since the last triggering.

The default value is 0.

request/gps_v2_bricklet/<UID>/get_date_time_callback_period
Response payload:
  • period -- int

Returns the period as set by request/gps_v2_bricklet/<UID>/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 corresponding .../register/... topic and an optional suffix. This suffix can be used to deregister the callback later.

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.

register/gps_v2_bricklet/<UID>/pulse_per_second
Request payload:
  • register -- bool

A callback can be registered for this event by publishing to the .../register/gps_v2_bricklet/<UID>/pulse_per_second[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/gps_v2_bricklet/<UID>/pulse_per_second[/<SUFFIX>] topic for each registered suffix.

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.

register/gps_v2_bricklet/<UID>/coordinates
Request payload:
  • register -- bool
Response payload:
  • latitude -- int
  • ns -- char
  • longitude -- int
  • ew -- char

A callback can be registered for this event by publishing to the .../register/gps_v2_bricklet/<UID>/coordinates[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/gps_v2_bricklet/<UID>/coordinates[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v2_bricklet/<UID>/set_coordinates_callback_period. The parameters are the same as for request/gps_v2_bricklet/<UID>/get_coordinates.

The register/gps_v2_bricklet/<UID>/coordinates callback is only triggered if the coordinates changed since the last triggering and if there is currently a fix as indicated by request/gps_v2_bricklet/<UID>/get_status.

register/gps_v2_bricklet/<UID>/status
Request payload:
  • register -- bool
Response payload:
  • has_fix -- bool
  • satellites_view -- int

A callback can be registered for this event by publishing to the .../register/gps_v2_bricklet/<UID>/status[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/gps_v2_bricklet/<UID>/status[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v2_bricklet/<UID>/set_status_callback_period. The parameters are the same as for request/gps_v2_bricklet/<UID>/get_status.

The register/gps_v2_bricklet/<UID>/status callback is only triggered if the status changed since the last triggering.

register/gps_v2_bricklet/<UID>/altitude
Request payload:
  • register -- bool
Response payload:
  • altitude -- int
  • geoidal_separation -- int

A callback can be registered for this event by publishing to the .../register/gps_v2_bricklet/<UID>/altitude[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/gps_v2_bricklet/<UID>/altitude[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v2_bricklet/<UID>/set_altitude_callback_period. The parameters are the same as for request/gps_v2_bricklet/<UID>/get_altitude.

The register/gps_v2_bricklet/<UID>/altitude callback is only triggered if the altitude changed since the last triggering and if there is currently a fix as indicated by request/gps_v2_bricklet/<UID>/get_status.

register/gps_v2_bricklet/<UID>/motion
Request payload:
  • register -- bool
Response payload:
  • course -- int
  • speed -- int

A callback can be registered for this event by publishing to the .../register/gps_v2_bricklet/<UID>/motion[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/gps_v2_bricklet/<UID>/motion[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v2_bricklet/<UID>/set_motion_callback_period. The parameters are the same as for request/gps_v2_bricklet/<UID>/get_motion.

The register/gps_v2_bricklet/<UID>/motion callback is only triggered if the motion changed since the last triggering and if there is currently a fix as indicated by request/gps_v2_bricklet/<UID>/get_status.

register/gps_v2_bricklet/<UID>/date_time
Request payload:
  • register -- bool
Response payload:
  • date -- int
  • time -- int

A callback can be registered for this event by publishing to the .../register/gps_v2_bricklet/<UID>/date_time[/<SUFFIX>] topic with the payload "true". An added callback can be removed by publishing to the same topic with the payload "false". To support multiple (de)registrations, e.g. for message filtering, an optional suffix can be used.

If the callback is triggered, a message with it's payload is published under the corresponding .../callback/gps_v2_bricklet/<UID>/date_time[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v2_bricklet/<UID>/set_date_time_callback_period. The parameters are the same as for request/gps_v2_bricklet/<UID>/get_date_time.

The register/gps_v2_bricklet/<UID>/date_time callback is only triggered if the date or time changed since the last triggering.