Shell - GPS Bricklet

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

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

Examples

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

Simple

Download (example-simple.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your GPS Bricklet

# Get current coordinates
tinkerforge call gps-bricklet $uid get-coordinates

Callback

Download (example-callback.sh)

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#!/bin/sh
# Connects to localhost:4223 by default, use --host and --port to change this

uid=XYZ # Change XYZ to the UID of your GPS Bricklet

# Handle incoming coordinates callbacks
tinkerforge dispatch gps-bricklet $uid 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!
tinkerforge call gps-bricklet $uid set-coordinates-callback-period 1000

echo "Press key to exit"; read dummy

kill -- -$$ # Stop callback dispatch in background

API

Possible exit codes for all tinkerforge commands are:

  • 1: interrupted (ctrl+c)
  • 2: syntax error
  • 21: Python 2.5 or newer is required
  • 22: Python argparse module is missing
  • 23: socket error
  • 24: other exception
  • 25: invalid placeholder in format string
  • 26: authentication error
  • 201: timeout occurred
  • 209: invalid argument value
  • 210: function is not supported
  • 211: unknown error

Command Structure

The common options of the call and dispatch commands are documented here. The specific command structure is shown below.

tinkerforge call gps-bricklet [<option>..] <uid> <function> [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The call command is used to call a function of the GPS Bricklet. It can take several options:

  • --help shows help for the specific call command and exits
  • --list-functions shows a list of known functions of the GPS Bricklet and exits
tinkerforge dispatch gps-bricklet [<option>..] <uid> <callback>
Parameters:
  • <uid> -- string
  • <callback> -- string

The dispatch command is used to dispatch a callback of the GPS Bricklet. It can take several options:

  • --help shows help for the specific dispatch command and exits
  • --list-callbacks shows a list of known callbacks of the GPS Bricklet and exits
tinkerforge call gps-bricklet <uid> <function> [<option>..] [<argument>..]
Parameters:
  • <uid> -- string
  • <function> -- string

The <function> to be called can take different options depending of its kind. All functions can take the following options:

  • --help shows help for the specific function and exits

Getter functions can take the following options:

  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Setter functions can take the following options:

  • --expect-response requests response and waits for it

The --expect-response option for setter functions allows to detect timeouts and other error conditions calls of setters as well. The device will then send a response for this purpose. If this option is not given for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

tinkerforge dispatch gps-bricklet <uid> <callback> [<option>..]
Parameters:
  • <uid> -- string
  • <callback> -- string

The <callback> to be dispatched can take several options:

  • --help shows help for the specific callback and exits
  • --execute <command> shell command line to execute for each incoming response (see section about output formatting for details)

Basic Functions

tinkerforge call gps-bricklet <uid> get-coordinates
Output:
  • latitude -- int
  • ns -- char
  • longitude -- int
  • ew -- char
  • pdop -- int
  • hdop -- int
  • vdop -- int
  • epe -- int

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).

PDOP, HDOP and VDOP are the dilution of precision (DOP) values. They specify the additional multiplicative effect of GPS satellite geometry on GPS precision. See here for more information. The values are give in hundredths.

EPE is the "Estimated Position Error". The EPE is given in cm. This is not the absolute maximum error, it is the error with a specific confidence. See here for more information.

This data is only valid if there is currently a fix as indicated by get-status.

tinkerforge call gps-bricklet <uid> get-status
Output:
  • fix -- int (has symbols)
  • satellites-view -- int
  • satellites-used -- int

Returns the current fix status, the number of satellites that are in view and the number of satellites that are currently used.

Possible fix status values can be:

Value Description
1 No Fix, get-coordinates, get-altitude and get-motion return invalid data
2 2D Fix, only get-coordinates and get-motion return valid data
3 3D Fix, get-coordinates, get-altitude and get-motion return valid data

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

The following symbols are available for this function:

  • fix-no-fix = 1, for fix
  • fix-2d-fix = 2, for fix
  • fix-3d-fix = 3, for fix
tinkerforge call gps-bricklet <uid> get-altitude
Output:
  • 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 get-status.

tinkerforge call gps-bricklet <uid> get-motion
Output:
  • 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 get-status.

tinkerforge call gps-bricklet <uid> get-date-time
Output:
  • 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 14.05.13 as date and 195923568 means 19:59:23.568 as time.

Advanced Functions

tinkerforge call gps-bricklet <uid> restart <restart-type>
Parameters:
  • <restart-type> -- int (has symbols)
Output:

no output

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:

  • restart-type-hot-start = 0, for <restart-type>
  • restart-type-warm-start = 1, for <restart-type>
  • restart-type-cold-start = 2, for <restart-type>
  • restart-type-factory-reset = 3, for <restart-type>
tinkerforge call gps-bricklet <uid> get-identity
Output:
  • uid -- string
  • connected-uid -- string
  • position -- char
  • hardware-version -- int,int,int
  • firmware-version -- int,int,int
  • device-identifier -- int (has symbols)

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

Callback Configuration Functions

tinkerforge call gps-bricklet <uid> set-coordinates-callback-period <period>
Parameters:
  • <period> -- int
Output:

no output

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

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

The default value is 0.

tinkerforge call gps-bricklet <uid> get-coordinates-callback-period
Output:
  • period -- int

Returns the period as set by set-coordinates-callback-period.

tinkerforge call gps-bricklet <uid> set-status-callback-period <period>
Parameters:
  • <period> -- int
Output:

no output

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

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

The default value is 0.

tinkerforge call gps-bricklet <uid> get-status-callback-period
Output:
  • period -- int

Returns the period as set by set-status-callback-period.

tinkerforge call gps-bricklet <uid> set-altitude-callback-period <period>
Parameters:
  • <period> -- int
Output:

no output

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

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

The default value is 0.

tinkerforge call gps-bricklet <uid> get-altitude-callback-period
Output:
  • period -- int

Returns the period as set by set-altitude-callback-period.

tinkerforge call gps-bricklet <uid> set-motion-callback-period <period>
Parameters:
  • <period> -- int
Output:

no output

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

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

The default value is 0.

tinkerforge call gps-bricklet <uid> get-motion-callback-period
Output:
  • period -- int

Returns the period as set by set-motion-callback-period.

tinkerforge call gps-bricklet <uid> set-date-time-callback-period <period>
Parameters:
  • <period> -- int
Output:

no output

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

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

The default value is 0.

tinkerforge call gps-bricklet <uid> get-date-time-callback-period
Output:
  • period -- int

Returns the period as set by set-date-time-callback-period.

Callbacks

Callbacks can be used to receive time critical or recurring data from the device:

tinkerforge dispatch gps-bricklet <uid> example

The available callbacks 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.

tinkerforge dispatch gps-bricklet <uid> coordinates
Output:
  • latitude -- int
  • ns -- char
  • longitude -- int
  • ew -- char
  • pdop -- int
  • hdop -- int
  • vdop -- int
  • epe -- int

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 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.

tinkerforge dispatch gps-bricklet <uid> status
Output:
  • fix -- int (has symbols)
  • satellites-view -- int
  • satellites-used -- 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 status callback is only triggered if the status changed since the last triggering.

The following symbols are available for this function:

  • fix-no-fix = 1, for fix
  • fix-2d-fix = 2, for fix
  • fix-3d-fix = 3, for fix
tinkerforge dispatch gps-bricklet <uid> altitude
Output:
  • 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 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.

tinkerforge dispatch gps-bricklet <uid> motion
Output:
  • 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 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.

tinkerforge dispatch gps-bricklet <uid> date-time
Output:
  • 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 date-time callback is only triggered if the date or time changed since the last triggering.