Software / API Bindings / MQTT / API Reference and Examples / Bricklets / GPS Bricklet 3.0

MQTT - GPS Bricklet 3.0¶

This is the description of the MQTT API bindings for the GPS Bricklet 3.0. General information and technical specifications for the GPS Bricklet 3.0 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)

# Change XYZ to the UID of your GPS Bricklet 3.0

setup:
    # Get current coordinates
    subscribe to tinkerforge/response/gps_v3_bricklet/XYZ/get_coordinates
    publish '' to tinkerforge/request/gps_v3_bricklet/XYZ/get_coordinates

Callback¶

Download (example-callback.txt)

# Change XYZ to the UID of your GPS Bricklet 3.0

setup:
    # Handle incoming coordinates callbacks
    subscribe to tinkerforge/callback/gps_v3_bricklet/XYZ/coordinates
    publish '{"register": true}' to tinkerforge/register/gps_v3_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_v3_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 member _ERROR. It is published on the corresponding response topic: .../response/... for .../request/... and .../callback/... for .../register/....

Basic Functions¶

request/gps_v3_bricklet/<UID>/get_coordinates¶

Request:	empty payload
Response:	latitude – Type: int, Unit: 1/1000000 °, Range: [0 to 90000000] ns – Type: char, Range: ["N", "S"] longitude – Type: int, Unit: 1/1000000 °, Range: [0 to 180000000] ew – Type: char, Range: ["E", "W"]

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_v3_bricklet/<UID>/get_status.

request/gps_v3_bricklet/<UID>/get_status¶

Request:	empty payload
Response:	has_fix – Type: bool satellites_view – Type: int, Range: [0 to 255]

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

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

request/gps_v3_bricklet/<UID>/get_altitude¶

Request:	empty payload
Response:	altitude – Type: int, Unit: 1 cm, Range: [-2³¹ to 2³¹ - 1] geoidal_separation – Type: int, Unit: 1 cm, Range: [-2³¹ to 2³¹ - 1]

Returns the current altitude and corresponding geoidal separation.

This data is only valid if there is currently a fix as indicated by request/gps_v3_bricklet/<UID>/get_status.

request/gps_v3_bricklet/<UID>/get_motion¶

Request:	empty payload
Response:	course – Type: int, Unit: 1/100 °, Range: [0 to 36000] speed – Type: int, Unit: 1/100 km/h, Range: [0 to 2³² - 1]

Returns the current course and speed. 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_v3_bricklet/<UID>/get_status.

request/gps_v3_bricklet/<UID>/get_date_time¶

Request:	empty payload
Response:	date – Type: int, Range: [10100 to 311299] time – Type: int, Range: [0 to 235959999]

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_v3_bricklet/<UID>/get_satellite_system_status¶

Request:	satellite_system – Type: int, Range: See symbols
Response:	satellite_numbers – Type: [int, ...], Length: variable, Range: [0 to 255] fix – Type: int, Range: See symbols pdop – Type: int, Unit: 1/100, Range: [0 to 2¹⁶ - 1] hdop – Type: int, Unit: 1/100, Range: [0 to 2¹⁶ - 1] vdop – Type: int, Unit: 1/100, Range: [0 to 2¹⁶ - 1]

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, GLONASS and Galileo are 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:

"no_fix" = 1
"2d_fix" = 2
"3d_fix" = 3

request/gps_v3_bricklet/<UID>/get_satellite_status¶

Request:	satellite_system – Type: int, Range: See symbols satellite_number – Type: int, Range: [1 to 32]
Response:	elevation – Type: int, Unit: 1 °, Range: [0 to 90] azimuth – Type: int, Unit: 1 °, Range: [0 to 359] snr – Type: int, Unit: 1 dB, Range: [0 to 99]

Returns the current elevation, azimuth and SNR for a given satellite and satellite system.

The available satellite numbers are:

GPS: 1-32
GLONASS: 65-96
Galileo: 301-332

The following symbols are available for this function:

For satellite_system:

"gps" = 0
"glonass" = 1
"galileo" = 2

Advanced Functions¶

request/gps_v3_bricklet/<UID>/restart¶

Request:	restart_type – Type: int, Range: See symbols
Response:	no response

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:

"hot_start" = 0
"warm_start" = 1
"cold_start" = 2
"factory_reset" = 3

request/gps_v3_bricklet/<UID>/set_fix_led_config¶

Request:	config – Type: int, Range: See symbols, Default: 3
Response:	no response

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
"show_heartbeat" = 2
"show_fix" = 3
"show_pps" = 4

request/gps_v3_bricklet/<UID>/get_fix_led_config¶

Request:	empty payload
Response:	config – Type: int, Range: See symbols, Default: 3

Returns the configuration as set by request/gps_v3_bricklet/<UID>/set_fix_led_config

The following symbols are available for this function:

For config:

"off" = 0
"on" = 1
"show_heartbeat" = 2
"show_fix" = 3
"show_pps" = 4

request/gps_v3_bricklet/<UID>/set_sbas_config¶

Request:	sbas_config – Type: int, Range: See symbols, Default: 0
Response:	no response

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.

The following symbols are available for this function:

For sbas_config:

"enabled" = 0
"disabled" = 1

request/gps_v3_bricklet/<UID>/get_sbas_config¶

Request:	empty payload
Response:	sbas_config – Type: int, Range: See symbols, Default: 0

Returns the SBAS configuration as set by request/gps_v3_bricklet/<UID>/set_sbas_config

The following symbols are available for this function:

For sbas_config:

"enabled" = 0
"disabled" = 1

request/gps_v3_bricklet/<UID>/get_spitfp_error_count¶

Request:	empty payload
Response:	error_count_ack_checksum – Type: int, Range: [0 to 2³² - 1] error_count_message_checksum – Type: int, Range: [0 to 2³² - 1] error_count_frame – Type: int, Range: [0 to 2³² - 1] error_count_overflow – Type: int, Range: [0 to 2³² - 1]

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_v3_bricklet/<UID>/set_status_led_config¶

Request:	config – Type: int, Range: See symbols, Default: 3
Response:	no response

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
"show_heartbeat" = 2
"show_status" = 3

request/gps_v3_bricklet/<UID>/get_status_led_config¶

Request:	empty payload
Response:	config – Type: int, Range: See symbols, Default: 3

Returns the configuration as set by request/gps_v3_bricklet/<UID>/set_status_led_config

The following symbols are available for this function:

For config:

"off" = 0
"on" = 1
"show_heartbeat" = 2
"show_status" = 3

request/gps_v3_bricklet/<UID>/get_chip_temperature¶

Request:	empty payload
Response:	temperature – Type: int, Unit: 1 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the temperature 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_v3_bricklet/<UID>/reset¶

Request:	empty payload
Response:	no response

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_v3_bricklet/<UID>/get_identity¶

Request:

empty payload

Response:

uid – Type: string, Length: up to 8
connected_uid – Type: string, Length: up to 8
position – Type: char, Range: ["a" to "h", "z"]
hardware_version – Type: [int, ...], Length: 3

0: major – Type: int, Range: [0 to 255]
1: minor – Type: int, Range: [0 to 255]
2: revision – Type: int, Range: [0 to 255]

firmware_version – Type: [int, ...], Length: 3

0: major – Type: int, Range: [0 to 255]
1: minor – Type: int, Range: [0 to 255]
2: revision – Type: int, Range: [0 to 255]

device_identifier – Type: int, Range: [0 to 2¹⁶ - 1]
_display_name – Type: 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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

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 3.0's name in a human readable form.

Callback Configuration Functions¶

request/gps_v3_bricklet/<UID>/set_coordinates_callback_period¶

Request:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

Sets the period with which the register/gps_v3_bricklet/<UID>/coordinates callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v3_bricklet/<UID>/coordinates callback is only triggered if the coordinates changed since the last triggering.

request/gps_v3_bricklet/<UID>/get_coordinates_callback_period¶

Request:	empty payload
Response:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by request/gps_v3_bricklet/<UID>/set_coordinates_callback_period.

request/gps_v3_bricklet/<UID>/set_status_callback_period¶

Request:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

Sets the period with which the register/gps_v3_bricklet/<UID>/status callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v3_bricklet/<UID>/status callback is only triggered if the status changed since the last triggering.

request/gps_v3_bricklet/<UID>/get_status_callback_period¶

Request:	empty payload
Response:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by request/gps_v3_bricklet/<UID>/set_status_callback_period.

request/gps_v3_bricklet/<UID>/set_altitude_callback_period¶

Request:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

Sets the period with which the register/gps_v3_bricklet/<UID>/altitude callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v3_bricklet/<UID>/altitude callback is only triggered if the altitude changed since the last triggering.

request/gps_v3_bricklet/<UID>/get_altitude_callback_period¶

Request:	empty payload
Response:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by request/gps_v3_bricklet/<UID>/set_altitude_callback_period.

request/gps_v3_bricklet/<UID>/set_motion_callback_period¶

Request:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

Sets the period with which the register/gps_v3_bricklet/<UID>/motion callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v3_bricklet/<UID>/motion callback is only triggered if the motion changed since the last triggering.

request/gps_v3_bricklet/<UID>/get_motion_callback_period¶

Request:	empty payload
Response:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by request/gps_v3_bricklet/<UID>/set_motion_callback_period.

request/gps_v3_bricklet/<UID>/set_date_time_callback_period¶

Request:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0
Response:	no response

Sets the period with which the register/gps_v3_bricklet/<UID>/date_time callback is triggered periodically. A value of 0 turns the callback off.

The register/gps_v3_bricklet/<UID>/date_time callback is only triggered if the date or time changed since the last triggering.

request/gps_v3_bricklet/<UID>/get_date_time_callback_period¶

Request:	empty payload
Response:	period – Type: int, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by request/gps_v3_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_v3_bricklet/<UID>/pulse_per_second¶

Register Request:	register – Type: bool
Callback Response:	empty payload

A callback can be registered for this event by publishing to the .../register/gps_v3_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_v3_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_v3_bricklet/<UID>/coordinates¶

Register Request:	register – Type: bool
Callback Response:	latitude – Type: int, Unit: 1/1000000 °, Range: [0 to 90000000] ns – Type: char, Range: ["N", "S"] longitude – Type: int, Unit: 1/1000000 °, Range: [0 to 180000000] ew – Type: char, Range: ["E", "W"]

A callback can be registered for this event by publishing to the .../register/gps_v3_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_v3_bricklet/<UID>/coordinates[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v3_bricklet/<UID>/set_coordinates_callback_period. The parameters are the same as for request/gps_v3_bricklet/<UID>/get_coordinates.

The register/gps_v3_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_v3_bricklet/<UID>/get_status.

register/gps_v3_bricklet/<UID>/status¶

Register Request:	register – Type: bool
Callback Response:	has_fix – Type: bool satellites_view – Type: int, Range: [0 to 255]

A callback can be registered for this event by publishing to the .../register/gps_v3_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_v3_bricklet/<UID>/status[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v3_bricklet/<UID>/set_status_callback_period. The parameters are the same as for request/gps_v3_bricklet/<UID>/get_status.

The register/gps_v3_bricklet/<UID>/status callback is only triggered if the status changed since the last triggering.

register/gps_v3_bricklet/<UID>/altitude¶

Register Request:	register – Type: bool
Callback Response:	altitude – Type: int, Unit: 1 cm, Range: [-2³¹ to 2³¹ - 1] geoidal_separation – Type: int, Unit: 1 cm, Range: [-2³¹ to 2³¹ - 1]

A callback can be registered for this event by publishing to the .../register/gps_v3_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_v3_bricklet/<UID>/altitude[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v3_bricklet/<UID>/set_altitude_callback_period. The parameters are the same as for request/gps_v3_bricklet/<UID>/get_altitude.

The register/gps_v3_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_v3_bricklet/<UID>/get_status.

register/gps_v3_bricklet/<UID>/motion¶

Register Request:	register – Type: bool
Callback Response:	course – Type: int, Unit: 1/100 °, Range: [0 to 36000] speed – Type: int, Unit: 1/100 km/h, Range: [0 to 2³² - 1]

A callback can be registered for this event by publishing to the .../register/gps_v3_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_v3_bricklet/<UID>/motion[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v3_bricklet/<UID>/set_motion_callback_period. The parameters are the same as for request/gps_v3_bricklet/<UID>/get_motion.

The register/gps_v3_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_v3_bricklet/<UID>/get_status.

register/gps_v3_bricklet/<UID>/date_time¶

Register Request:	register – Type: bool
Callback Response:	date – Type: int, Range: [10100 to 311299] time – Type: int, Range: [0 to 235959999]

A callback can be registered for this event by publishing to the .../register/gps_v3_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_v3_bricklet/<UID>/date_time[/<SUFFIX>] topic for each registered suffix.

This callback is triggered periodically with the period that is set by request/gps_v3_bricklet/<UID>/set_date_time_callback_period. The parameters are the same as for request/gps_v3_bricklet/<UID>/get_date_time.

The register/gps_v3_bricklet/<UID>/date_time callback is only triggered if the date or time changed since the last triggering.

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

request/gps_v3_bricklet/<UID>/set_bootloader_mode¶

Request:	mode – Type: int, Range: See symbols
Response:	status – Type: int, Range: See 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
"bootloader_wait_for_reboot" = 2
"firmware_wait_for_reboot" = 3
"firmware_wait_for_erase_and_reboot" = 4

For status:

"ok" = 0
"invalid_mode" = 1
"no_change" = 2
"entry_function_not_present" = 3
"device_identifier_incorrect" = 4
"crc_mismatch" = 5

request/gps_v3_bricklet/<UID>/get_bootloader_mode¶

Request:	empty payload
Response:	mode – Type: int, Range: See symbols

Returns the current bootloader mode, see request/gps_v3_bricklet/<UID>/set_bootloader_mode.

The following symbols are available for this function:

For mode:

"bootloader" = 0
"firmware" = 1
"bootloader_wait_for_reboot" = 2
"firmware_wait_for_reboot" = 3
"firmware_wait_for_erase_and_reboot" = 4

request/gps_v3_bricklet/<UID>/set_write_firmware_pointer¶

Request:	pointer – Type: int, Unit: 1 B, Range: [0 to 2³² - 1]
Response:	no response

Sets the firmware pointer for request/gps_v3_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_v3_bricklet/<UID>/write_firmware¶

Request:	data – Type: [int, ...], Length: 64, Range: [0 to 255]
Response:	status – Type: int, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by request/gps_v3_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_v3_bricklet/<UID>/write_uid¶

Request:	uid – Type: int, Range: [0 to 2³² - 1]
Response:	no response

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_v3_bricklet/<UID>/read_uid¶

Request:	empty payload
Response:	uid – Type: int, Range: [0 to 2³² - 1]

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