PHP - GPS Bricklet

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

Examples

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

Simple

Download (ExampleSimple.php)

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<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletGPS.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletGPS;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your GPS Bricklet

$ipcon = new IPConnection(); // Create IP connection
$gps = new BrickletGPS(UID, $ipcon); // Create device object

$ipcon->connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected

// Get current coordinates
$coordinates = $gps->getCoordinates();

echo "Latitude: " . $coordinates['latitude']/1000000.0 . " °\n";
echo "N/S: " . $coordinates['ns'] . "\n";
echo "Longitude: " . $coordinates['longitude']/1000000.0 . " °\n";
echo "E/W: " . $coordinates['ew'] . "\n";

echo "Press key to exit\n";
fgetc(fopen('php://stdin', 'r'));
$ipcon->disconnect();

?>

Callback

Download (ExampleCallback.php)

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<?php

require_once('Tinkerforge/IPConnection.php');
require_once('Tinkerforge/BrickletGPS.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletGPS;

const HOST = 'localhost';
const PORT = 4223;
const UID = 'XYZ'; // Change XYZ to the UID of your GPS Bricklet

// Callback function for coordinates callback
function cb_coordinates($latitude, $ns, $longitude, $ew, $pdop, $hdop, $vdop, $epe)
{
    echo "Latitude: " . $latitude/1000000.0 . " °\n";
    echo "N/S: $ns\n";
    echo "Longitude: " . $longitude/1000000.0 . " °\n";
    echo "E/W: $ew\n";
    echo "\n";
}

$ipcon = new IPConnection(); // Create IP connection
$gps = new BrickletGPS(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->registerCallback(BrickletGPS::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->setCoordinatesCallbackPeriod(1000);

echo "Press ctrl+c to exit\n";
$ipcon->dispatchCallbacks(-1); // Dispatch callbacks forever

?>

API

Functions that return multiple values return them in an associative array.

Basic Functions

class BrickletGPS(string $uid, IPConnection $ipcon)
Parameters:
  • $uid – Type: string
  • $ipcon – Type: IPConnection
Returns:
  • $gps – Type: BrickletGPS

Creates an object with the unique device ID $uid:

<?php   $gps = new BrickletGPS('YOUR_DEVICE_UID', $ipcon);   ?>

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

array BrickletGPS::getCoordinates()
Return Array:
  • 'latitude' – Type: int, Unit: 1/1000000 °, Range: [0 to 90000000]
  • 'ns' – Type: string, Range: ['N', 'S']
  • 'longitude' – Type: int, Unit: 1/1000000 °, Range: [0 to 180000000]
  • 'ew' – Type: string, Range: ['E', 'W']
  • '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]
  • 'epe' – Type: int, Unit: 1 cm, 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.

EPE is the "Estimated Position Error". 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().

array BrickletGPS::getStatus()
Return Array:
  • 'fix' – Type: int, Range: See constants
  • 'satellites_view' – Type: int, Range: [0 to 255]
  • 'satellites_used' – Type: int, 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::FIX_NO_FIX = 1
  • BrickletGPS::FIX_2D_FIX = 2
  • BrickletGPS::FIX_3D_FIX = 3
array BrickletGPS::getAltitude()
Return Array:
  • '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 getStatus().

array BrickletGPS::getMotion()
Return Array:
  • '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 getStatus().

array BrickletGPS::getDateTime()
Return Array:
  • '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.

Advanced Functions

void BrickletGPS::restart(int $restart_type)
Parameters:
  • $restart_type – Type: int, 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 $restart_type:

  • BrickletGPS::RESTART_TYPE_HOT_START = 0
  • BrickletGPS::RESTART_TYPE_WARM_START = 1
  • BrickletGPS::RESTART_TYPE_COLD_START = 2
  • BrickletGPS::RESTART_TYPE_FACTORY_RESET = 3
array BrickletGPS::getIdentity()
Return Array:
  • 'uid' – Type: string, Length: up to 8
  • 'connected_uid' – Type: string, Length: up to 8
  • 'position' – Type: string, Range: ['a' to 'h', 'i', 'z']
  • 'hardware_version' – Type: array(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: array(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]

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). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

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

Callback Configuration Functions

void BrickletGPS::registerCallback(int $callback_id, callable $callback, mixed $user_data=NULL)
Parameters:
  • $callback_id – Type: int
  • $callback – Type: callable
  • $user_data – Type: mixed

Registers the given $function with the given $callback_id. The optional $user_data will be passed as the last parameter to the function.

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

void BrickletGPS::setCoordinatesCallbackPeriod(int $period)
Parameters:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Sets the period 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.

int BrickletGPS::getCoordinatesCallbackPeriod()
Returns:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by setCoordinatesCallbackPeriod().

void BrickletGPS::setStatusCallbackPeriod(int $period)
Parameters:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Sets the period 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.

int BrickletGPS::getStatusCallbackPeriod()
Returns:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by setStatusCallbackPeriod().

void BrickletGPS::setAltitudeCallbackPeriod(int $period)
Parameters:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Sets the period 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.

int BrickletGPS::getAltitudeCallbackPeriod()
Returns:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by setAltitudeCallbackPeriod().

void BrickletGPS::setMotionCallbackPeriod(int $period)
Parameters:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Sets the period 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.

int BrickletGPS::getMotionCallbackPeriod()
Returns:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by setMotionCallbackPeriod().

void BrickletGPS::setDateTimeCallbackPeriod(int $period)
Parameters:
  • $period – Type: int, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Sets the period 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.

int BrickletGPS::getDateTimeCallbackPeriod()
Returns:
  • $period – Type: int, 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 with the registerCallback() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

<?php

function myCallback($param)
{
    echo $param . "\n";
}

$gps->registerCallback(BrickletGPS::CALLBACK_EXAMPLE, 'myCallback');

?>

The available constants with corresponding function signatures 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.

int BrickletGPS::CALLBACK_COORDINATES
<?php   void callback(int $latitude, string $ns, int $longitude, string $ew, int $pdop, int $hdop, int $vdop, int $epe [, mixed $user_data])   ?>
Callback Parameters:
  • $latitude – Type: int, Unit: 1/1000000 °, Range: [0 to 90000000]
  • $ns – Type: string, Range: ['N', 'S']
  • $longitude – Type: int, Unit: 1/1000000 °, Range: [0 to 180000000]
  • $ew – Type: string, Range: ['E', 'W']
  • $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]
  • $epe – Type: int, Unit: 1 cm, Range: [0 to 216 - 1]
  • $user_data – Type: mixed

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

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 getStatus().

int BrickletGPS::CALLBACK_STATUS
<?php   void callback(int $fix, int $satellites_view, int $satellites_used [, mixed $user_data])   ?>
Callback Parameters:
  • $fix – Type: int, Range: See constants
  • $satellites_view – Type: int, Range: [0 to 255]
  • $satellites_used – Type: int, Range: [0 to 255]
  • $user_data – Type: mixed

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

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

The following constants are available for this function:

For $fix:

  • BrickletGPS::FIX_NO_FIX = 1
  • BrickletGPS::FIX_2D_FIX = 2
  • BrickletGPS::FIX_3D_FIX = 3
int BrickletGPS::CALLBACK_ALTITUDE
<?php   void callback(int $altitude, int $geoidal_separation [, mixed $user_data])   ?>
Callback Parameters:
  • $altitude – Type: int, Unit: 1 cm, Range: [-231 to 231 - 1]
  • $geoidal_separation – Type: int, Unit: 1 cm, Range: [-231 to 231 - 1]
  • $user_data – Type: mixed

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

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 getStatus().

int BrickletGPS::CALLBACK_MOTION
<?php   void callback(int $course, int $speed [, mixed $user_data])   ?>
Callback Parameters:
  • $course – Type: int, Unit: 1/100 °, Range: [0 to 36000]
  • $speed – Type: int, Unit: 1/100 km/h, Range: [0 to 232 - 1]
  • $user_data – Type: mixed

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

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 getStatus().

int BrickletGPS::CALLBACK_DATE_TIME
<?php   void callback(int $date, int $time [, mixed $user_data])   ?>
Callback Parameters:
  • $date – Type: int, Range: [10100 to 311299]
  • $time – Type: int, Range: [0 to 235959999]
  • $user_data – Type: mixed

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

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

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

array BrickletGPS::getAPIVersion()
Return Array:
  • $api_version – Type: array(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]

Returns the version of the API definition 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.

bool BrickletGPS::getResponseExpected(int $function_id)
Parameters:
  • $function_id – Type: int, Range: See constants
Returns:
  • $response_expected – 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 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 $function_id:

  • BrickletGPS::FUNCTION_RESTART = 6
  • BrickletGPS::FUNCTION_SET_COORDINATES_CALLBACK_PERIOD = 7
  • BrickletGPS::FUNCTION_SET_STATUS_CALLBACK_PERIOD = 9
  • BrickletGPS::FUNCTION_SET_ALTITUDE_CALLBACK_PERIOD = 11
  • BrickletGPS::FUNCTION_SET_MOTION_CALLBACK_PERIOD = 13
  • BrickletGPS::FUNCTION_SET_DATE_TIME_CALLBACK_PERIOD = 15
void BrickletGPS::setResponseExpected(int $function_id, bool $response_expected)
Parameters:
  • $function_id – Type: int, Range: See constants
  • $response_expected – Type: bool

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 $function_id:

  • BrickletGPS::FUNCTION_RESTART = 6
  • BrickletGPS::FUNCTION_SET_COORDINATES_CALLBACK_PERIOD = 7
  • BrickletGPS::FUNCTION_SET_STATUS_CALLBACK_PERIOD = 9
  • BrickletGPS::FUNCTION_SET_ALTITUDE_CALLBACK_PERIOD = 11
  • BrickletGPS::FUNCTION_SET_MOTION_CALLBACK_PERIOD = 13
  • BrickletGPS::FUNCTION_SET_DATE_TIME_CALLBACK_PERIOD = 15
void BrickletGPS::setResponseExpectedAll(bool $response_expected)
Parameters:
  • $response_expected – Type: bool

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

Constants

int BrickletGPS::DEVICE_IDENTIFIER

This constant is used to identify a GPS Bricklet.

The getIdentity() function and the IPConnection::CALLBACK_ENUMERATE callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

string BrickletGPS::DEVICE_DISPLAY_NAME

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