Mathematica - GPS Bricklet

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

Examples

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

Simple

Download (ExampleSimple.nb)

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Needs["NETLink`"]
LoadNETAssembly["Tinkerforge",NotebookDirectory[]<>"../../.."]

host="localhost"
port=4223
uid="XYZ"(*Change XYZ to the UID of your GPS Bricklet*)

(*Create IPConnection and device object*)
ipcon=NETNew["Tinkerforge.IPConnection"]
gps=NETNew["Tinkerforge.BrickletGPS",uid,ipcon]
ipcon@Connect[host,port]

(*Get current coordinates*)
latitude=0;ns=0;longitude=0;ew=0;pdop=0;hdop=0;vdop=0;epe=0
gps@GetCoordinates[latitude,ns,longitude,ew,pdop,hdop,vdop,epe]

Print["Latitude: "<>ToString[N[Quantity[latitude,"°/1000000"]]]]
Print["N/S: "<>FromCharacterCode[ns]]
Print["Longitude: "<>ToString[N[Quantity[longitude,"°/1000000"]]]]
Print["E/W: "<>FromCharacterCode[ew]]

(*Clean up*)
ipcon@Disconnect[]
ReleaseNETObject[gps]
ReleaseNETObject[ipcon]

Callback

Download (ExampleCallback.nb)

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Needs["NETLink`"]
LoadNETAssembly["Tinkerforge",NotebookDirectory[]<>"../../.."]

host="localhost"
port=4223
uid="XYZ"(*Change XYZ to the UID of your GPS Bricklet*)

(*Create IPConnection and device object*)
ipcon=NETNew["Tinkerforge.IPConnection"]
gps=NETNew["Tinkerforge.BrickletGPS",uid,ipcon]
ipcon@Connect[host,port]

(*Callback function for coordinates callback*)
CoordinatesCB[sender_,latitude_,ns_,longitude_,ew_,pdop_,hdop_,vdop_,epe_]:=
 Module[{},
  Print["Latitude: "<>ToString[N[Quantity[latitude,"°/1000000"]]]];
  Print["N/S: "<>FromCharacterCode[ns]];
  Print["Longitude: "<>ToString[N[Quantity[longitude,"°/1000000"]]]];
  Print["E/W: "<>FromCharacterCode[ew]]
 ]

AddEventHandler[gps@CoordinatesCallback,CoordinatesCB]

(*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@SetCoordinatesCallbackPeriod[1000]

Input["Click OK to exit"]

(*Clean up*)
ipcon@Disconnect[]
ReleaseNETObject[gps]
ReleaseNETObject[ipcon]

API

Generally, every method of the Mathematica bindings that returns a value can throw a Tinkerforge.TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody plugs the device out). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Since .NET/Link does not support multiple return values directly, we use the out keyword to return multiple values from a method. For further information about the out keyword in .NET/Link see the corresponding Mathematica .NET/Link documentation.

The namespace for all Brick/Bricklet bindings and the IPConnection is Tinkerforge.*.

Basic Functions

BrickletGPS[uid, ipcon] → gps
Parameters:
  • uid – Type: String
  • ipcon – Type: NETObject[IPConnection]
Returns:
  • gps – Type: NETObject[BrickletGPS]

Creates an object with the unique device ID uid:

gps=NETNew["Tinkerforge.BrickletGPS","YOUR_DEVICE_UID",ipcon]

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

The .NET runtime has built-in garbage collection that frees objects that are no longer in use by a program. But because Mathematica can not automatically tell when a Mathematica "program" doesn't use a .NET object anymore, this has to be done by the program. For this the ReleaseNETObject[] function is used in the examples.

For further information about object management in .NET/Link see the corresponding Mathematica .NET/Link documentation.

BrickletGPS@GetCoordinates[out latitude, out ns, out longitude, out ew, out pdop, out hdop, out vdop, out epe] → Null
Output Parameters:
  • latitude – Type: Integer, Range: [0 to 232 - 1]
  • ns – Type: Integer
  • longitude – Type: Integer, Range: [0 to 232 - 1]
  • ew – Type: Integer
  • pdop – Type: Integer, Range: [0 to 216 - 1]
  • hdop – Type: Integer, Range: [0 to 216 - 1]
  • vdop – Type: Integer, Range: [0 to 216 - 1]
  • epe – Type: Integer, Range: [0 to 216 - 1]

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 GetStatus[].

BrickletGPS@GetStatus[out fix, out satellitesView, out satellitesUsed] → Null
Output Parameters:
  • fix – Type: Integer, Range: See constants
  • satellitesView – Type: Integer, Range: [0 to 255]
  • satellitesUsed – Type: Integer, Range: [0 to 255]

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, GetCoordinates[], GetAltitude[] and GetMotion[] return invalid data
2 2D Fix, only GetCoordinates[] and GetMotion[] return valid data
3 3D Fix, GetCoordinates[], GetAltitude[] and GetMotion[] return valid data

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

The following constants are available for this function:

For fix:

  • BrickletGPS`FIXUNOUFIX = 1
  • BrickletGPS`FIXU2DUFIX = 2
  • BrickletGPS`FIXU3DUFIX = 3
BrickletGPS@GetAltitude[out altitude, out geoidalSeparation] → Null
Output Parameters:
  • altitude – Type: Integer, Range: [-231 to 231 - 1]
  • geoidalSeparation – Type: Integer, Range: [-231 to 231 - 1]

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 GetStatus[].

BrickletGPS@GetMotion[out course, out speed] → Null
Output Parameters:
  • course – Type: Integer, Range: [0 to 232 - 1]
  • speed – Type: Integer, Range: [0 to 232 - 1]

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 GetStatus[].

BrickletGPS@GetDateTime[out date, out time] → Null
Output Parameters:
  • date – Type: Integer, Range: [0 to 232 - 1]
  • time – Type: Integer, Range: [0 to 232 - 1]

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.

Advanced Functions

BrickletGPS@Restart[restartType] → Null
Parameters:
  • restartType – Type: Integer, Range: See constants

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:

For restartType:

  • BrickletGPS`RESTARTUTYPEUHOTUSTART = 0
  • BrickletGPS`RESTARTUTYPEUWARMUSTART = 1
  • BrickletGPS`RESTARTUTYPEUCOLDUSTART = 2
  • BrickletGPS`RESTARTUTYPEUFACTORYURESET = 3
BrickletGPS@GetAPIVersion[] → {apiVersion1, apiVersion2, apiVersion3}
Returns:
  • apiVersioni – Type: Integer, Range: [0 to 255]

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.

BrickletGPS@GetResponseExpected[functionId] → responseExpected
Parameters:
  • functionId – Type: Integer, Range: See constants
Returns:
  • responseExpected – Type: True/False

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 SetResponseExpected[]. 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.

The following constants are available for this function:

For functionId:

  • BrickletGPS`FUNCTIONURESTART = 6
  • BrickletGPS`FUNCTIONUSETUCOORDINATESUCALLBACKUPERIOD = 7
  • BrickletGPS`FUNCTIONUSETUSTATUSUCALLBACKUPERIOD = 9
  • BrickletGPS`FUNCTIONUSETUALTITUDEUCALLBACKUPERIOD = 11
  • BrickletGPS`FUNCTIONUSETUMOTIONUCALLBACKUPERIOD = 13
  • BrickletGPS`FUNCTIONUSETUDATEUTIMEUCALLBACKUPERIOD = 15
BrickletGPS@SetResponseExpected[functionId, responseExpected] → Null
Parameters:
  • functionId – Type: Integer, Range: See constants
  • responseExpected – Type: True/False

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 constants are available for this function:

For functionId:

  • BrickletGPS`FUNCTIONURESTART = 6
  • BrickletGPS`FUNCTIONUSETUCOORDINATESUCALLBACKUPERIOD = 7
  • BrickletGPS`FUNCTIONUSETUSTATUSUCALLBACKUPERIOD = 9
  • BrickletGPS`FUNCTIONUSETUALTITUDEUCALLBACKUPERIOD = 11
  • BrickletGPS`FUNCTIONUSETUMOTIONUCALLBACKUPERIOD = 13
  • BrickletGPS`FUNCTIONUSETUDATEUTIMEUCALLBACKUPERIOD = 15
BrickletGPS@SetResponseExpectedAll[responseExpected] → Null
Parameters:
  • responseExpected – Type: True/False

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

BrickletGPS@GetIdentity[out uid, out connectedUid, out position, out {hardwareVersion1, hardwareVersion2, hardwareVersion3}, out {firmwareVersion1, firmwareVersion2, firmwareVersion3}, out deviceIdentifier] → Null
Output Parameters:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: Integer
  • hardwareVersioni – Type: Integer, Range: [0 to 255]
  • firmwareVersioni – Type: Integer, Range: [0 to 255]
  • deviceIdentifier – Type: Integer, Range: [0 to 216 - 1]

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.

Callback Configuration Functions

BrickletGPS@SetCoordinatesCallbackPeriod[period] → Null
Parameters:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

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

BrickletGPS@GetCoordinatesCallbackPeriod[] → period
Returns:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetCoordinatesCallbackPeriod[].

BrickletGPS@SetStatusCallbackPeriod[period] → Null
Parameters:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

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

BrickletGPS@GetStatusCallbackPeriod[] → period
Returns:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetStatusCallbackPeriod[].

BrickletGPS@SetAltitudeCallbackPeriod[period] → Null
Parameters:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

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

BrickletGPS@GetAltitudeCallbackPeriod[] → period
Returns:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetAltitudeCallbackPeriod[].

BrickletGPS@SetMotionCallbackPeriod[period] → Null
Parameters:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

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

BrickletGPS@GetMotionCallbackPeriod[] → period
Returns:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetMotionCallbackPeriod[].

BrickletGPS@SetDateTimeCallbackPeriod[period] → Null
Parameters:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

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

BrickletGPS@GetDateTimeCallbackPeriod[] → period
Returns:
  • period – Type: Integer, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetDateTimeCallbackPeriod[].

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by assigning a function to a callback property of the device object:

MyCallback[sender_,value_]:=Print["Value: "<>ToString[value]]

AddEventHandler[gps@ExampleCallback,MyCallback]

For further information about event handling using .NET/Link see the corresponding Mathematica .NET/Link documentation.

The available callback property and their 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.

event BrickletGPS@CoordinatesCallback[sender, latitude, ns, longitude, ew, pdop, hdop, vdop, epe]
Callback Parameters:
  • sender – Type: NETObject[BrickletGPS]
  • latitude – Type: Integer, Range: [0 to 232 - 1]
  • ns – Type: Integer
  • longitude – Type: Integer, Range: [0 to 232 - 1]
  • ew – Type: Integer
  • pdop – Type: Integer, Range: [0 to 216 - 1]
  • hdop – Type: Integer, Range: [0 to 216 - 1]
  • vdop – Type: Integer, Range: [0 to 216 - 1]
  • epe – Type: Integer, Range: [0 to 216 - 1]

This callback is triggered periodically with the period that is set by SetCoordinatesCallbackPeriod[]. The parameters are the same as for GetCoordinates[].

The CoordinatesCallback callback is only triggered if the coordinates changed since the last triggering and if there is currently a fix as indicated by GetStatus[].

event BrickletGPS@StatusCallback[sender, fix, satellitesView, satellitesUsed]
Callback Parameters:
  • sender – Type: NETObject[BrickletGPS]
  • fix – Type: Integer, Range: See constants
  • satellitesView – Type: Integer, Range: [0 to 255]
  • satellitesUsed – Type: Integer, Range: [0 to 255]

This callback is triggered periodically with the period that is set by SetStatusCallbackPeriod[]. The parameters are the same as for GetStatus[].

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

The following constants are available for this function:

For fix:

  • BrickletGPS`FIXUNOUFIX = 1
  • BrickletGPS`FIXU2DUFIX = 2
  • BrickletGPS`FIXU3DUFIX = 3
event BrickletGPS@AltitudeCallback[sender, altitude, geoidalSeparation]
Callback Parameters:
  • sender – Type: NETObject[BrickletGPS]
  • altitude – Type: Integer, Range: [-231 to 231 - 1]
  • geoidalSeparation – Type: Integer, Range: [-231 to 231 - 1]

This callback is triggered periodically with the period that is set by SetAltitudeCallbackPeriod[]. The parameters are the same as for GetAltitude[].

The AltitudeCallback callback is only triggered if the altitude changed since the last triggering and if there is currently a fix as indicated by GetStatus[].

event BrickletGPS@MotionCallback[sender, course, speed]
Callback Parameters:
  • sender – Type: NETObject[BrickletGPS]
  • course – Type: Integer, Range: [0 to 232 - 1]
  • speed – Type: Integer, Range: [0 to 232 - 1]

This callback is triggered periodically with the period that is set by SetMotionCallbackPeriod[]. The parameters are the same as for GetMotion[].

The MotionCallback callback is only triggered if the motion changed since the last triggering and if there is currently a fix as indicated by GetStatus[].

event BrickletGPS@DateTimeCallback[sender, date, time]
Callback Parameters:
  • sender – Type: NETObject[BrickletGPS]
  • date – Type: Integer, Range: [0 to 232 - 1]
  • time – Type: Integer, Range: [0 to 232 - 1]

This callback is triggered periodically with the period that is set by SetDateTimeCallbackPeriod[]. The parameters are the same as for GetDateTime[].

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

Constants

BrickletGPS`DEVICEUIDENTIFIER

This constant is used to identify a GPS Bricklet.

The GetIdentity[] function and the IPConnection@EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

BrickletGPS`DEVICEDISPLAYNAME

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