PHP - Joystick Bricklet

This is the description of the PHP API bindings for the Joystick Bricklet. General information and technical specifications for the Joystick 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/BrickletJoystick.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletJoystick;

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

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

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

// Get current position
$position = $j->getPosition();

echo "Position [X]: " . $position['x'] . "\n";
echo "Position [Y]: " . $position['y'] . "\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/BrickletJoystick.php');

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletJoystick;

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

// Callback function for pressed callback
function cb_pressed()
{
    echo "Pressed\n";
}

// Callback function for released callback
function cb_released()
{
    echo "Released\n";
}

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

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

// Register pressed callback to function cb_pressed
$j->registerCallback(BrickletJoystick::CALLBACK_PRESSED, 'cb_pressed');

// Register released callback to function cb_released
$j->registerCallback(BrickletJoystick::CALLBACK_RELEASED, 'cb_released');

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

?>

Find Borders

Download (ExampleFindBorders.php)

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<?php

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

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletJoystick;

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

// Callback function for position reached callback
function cb_positionReached($x, $y)
{
    if ($y == 100) {
        echo "Top\n";
    } elseif ($y == -100) {
        echo "Bottom\n";
    }

    if ($x == 100) {
        echo "Right\n";
    } elseif ($x == -100) {
        echo "Left\n";
    }

    echo "\n";
}

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

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

// Get threshold callbacks with a debounce time of 0.2 seconds (200ms)
$j->setDebouncePeriod(200);

// Register position reached callback to function cb_positionReached
$j->registerCallback(BrickletJoystick::CALLBACK_POSITION_REACHED, 'cb_positionReached');

// Configure threshold for position "outside of -99, -99 to 99, 99"
$j->setPositionCallbackThreshold('o', -99, 99, -99, 99);

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 BrickletJoystick(string $uid, IPConnection $ipcon)

Creates an object with the unique device ID $uid:

<?php   $joystick = new BrickletJoystick('YOUR_DEVICE_UID', $ipcon);   ?>

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

array BrickletJoystick::getPosition()

Returns the position of the Joystick. The value ranges between -100 and 100 for both axis. The middle position of the joystick is x=0, y=0. The returned values are averaged and calibrated (see calibrate()).

If you want to get the position periodically, it is recommended to use the CALLBACK_POSITION callback and set the period with setPositionCallbackPeriod().

The returned array has the keys x and y.

bool BrickletJoystick::isPressed()

Returns true if the button is pressed and false otherwise.

It is recommended to use the CALLBACK_PRESSED and CALLBACK_RELEASED callbacks to handle the button.

Advanced Functions

array BrickletJoystick::getAnalogValue()

Returns the values as read by a 12-bit analog-to-digital converter. The values are between 0 and 4095 for both axis.

Note

The values returned by getPosition() are averaged over several samples to yield less noise, while getAnalogValue() gives back raw unfiltered analog values. The only reason to use getAnalogValue() is, if you need the full resolution of the analog-to-digital converter.

If you want the analog values periodically, it is recommended to use the CALLBACK_ANALOG_VALUE callback and set the period with setAnalogValueCallbackPeriod().

The returned array has the keys x and y.

void BrickletJoystick::calibrate()

Calibrates the middle position of the Joystick. If your Joystick Bricklet does not return x=0 and y=0 in the middle position, call this function while the Joystick is standing still in the middle position.

The resulting calibration will be saved on the EEPROM of the Joystick Bricklet, thus you only have to calibrate it once.

array BrickletJoystick::getAPIVersion()

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.

bool BrickletJoystick::getResponseExpected(int $function_id)

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.

See setResponseExpected() for the list of function ID constants available for this function.

void BrickletJoystick::setResponseExpected(int $function_id, bool $response_expected)

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 function ID constants are available for this function:

  • BrickletJoystick::FUNCTION_CALIBRATE = 4
  • BrickletJoystick::FUNCTION_SET_POSITION_CALLBACK_PERIOD = 5
  • BrickletJoystick::FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 7
  • BrickletJoystick::FUNCTION_SET_POSITION_CALLBACK_THRESHOLD = 9
  • BrickletJoystick::FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 11
  • BrickletJoystick::FUNCTION_SET_DEBOUNCE_PERIOD = 13
void BrickletJoystick::setResponseExpectedAll(bool $response_expected)

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

array BrickletJoystick::getIdentity()

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.

The returned array has the keys uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

void BrickletJoystick::registerCallback(int $callback_id, callable $callback, mixed $user_data=NULL)

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 BrickletJoystick::setPositionCallbackPeriod(int $period)

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

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

The default value is 0.

int BrickletJoystick::getPositionCallbackPeriod()

Returns the period as set by setPositionCallbackPeriod().

void BrickletJoystick::setAnalogValueCallbackPeriod(int $period)

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

The CALLBACK_ANALOG_VALUE callback is only triggered if the analog values have changed since the last triggering.

The default value is 0.

int BrickletJoystick::getAnalogValueCallbackPeriod()

Returns the period as set by setAnalogValueCallbackPeriod().

void BrickletJoystick::setPositionCallbackThreshold(string $option, int $min_x, int $max_x, int $min_y, int $max_y)

Sets the thresholds for the CALLBACK_POSITION_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the position is outside the min and max values
'i' Callback is triggered when the position is inside the min and max values
'<' Callback is triggered when the position is smaller than the min values (max is ignored)
'>' Callback is triggered when the position is greater than the min values (max is ignored)

The default value is ('x', 0, 0, 0, 0).

The following constants are available for this function:

  • BrickletJoystick::THRESHOLD_OPTION_OFF = 'x'
  • BrickletJoystick::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletJoystick::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletJoystick::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletJoystick::THRESHOLD_OPTION_GREATER = '>'
array BrickletJoystick::getPositionCallbackThreshold()

Returns the threshold as set by setPositionCallbackThreshold().

The following constants are available for this function:

  • BrickletJoystick::THRESHOLD_OPTION_OFF = 'x'
  • BrickletJoystick::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletJoystick::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletJoystick::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletJoystick::THRESHOLD_OPTION_GREATER = '>'

The returned array has the keys option, min_x, max_x, min_y and max_y.

void BrickletJoystick::setAnalogValueCallbackThreshold(string $option, int $min_x, int $max_x, int $min_y, int $max_y)

Sets the thresholds for the CALLBACK_ANALOG_VALUE_REACHED callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the analog values are outside the min and max values
'i' Callback is triggered when the analog values are inside the min and max values
'<' Callback is triggered when the analog values are smaller than the min values (max is ignored)
'>' Callback is triggered when the analog values are greater than the min values (max is ignored)

The default value is ('x', 0, 0, 0, 0).

The following constants are available for this function:

  • BrickletJoystick::THRESHOLD_OPTION_OFF = 'x'
  • BrickletJoystick::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletJoystick::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletJoystick::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletJoystick::THRESHOLD_OPTION_GREATER = '>'
array BrickletJoystick::getAnalogValueCallbackThreshold()

Returns the threshold as set by setAnalogValueCallbackThreshold().

The following constants are available for this function:

  • BrickletJoystick::THRESHOLD_OPTION_OFF = 'x'
  • BrickletJoystick::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletJoystick::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletJoystick::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletJoystick::THRESHOLD_OPTION_GREATER = '>'

The returned array has the keys option, min_x, max_x, min_y and max_y.

void BrickletJoystick::setDebouncePeriod(int $debounce)

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

int BrickletJoystick::getDebouncePeriod()

Returns the debounce period as set by setDebouncePeriod().

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";
}

$joystick->registerCallback(BrickletJoystick::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 BrickletJoystick::CALLBACK_POSITION
<?php   void callback(int $x, int $y [, mixed $user_data])   ?>

This callback is triggered periodically with the period that is set by setPositionCallbackPeriod(). The parameter is the position of the Joystick.

The CALLBACK_POSITION callback is only triggered if the position has changed since the last triggering.

int BrickletJoystick::CALLBACK_ANALOG_VALUE
<?php   void callback(int $x, int $y [, mixed $user_data])   ?>

This callback is triggered periodically with the period that is set by setAnalogValueCallbackPeriod(). The parameters are the analog values of the Joystick.

The CALLBACK_ANALOG_VALUE callback is only triggered if the values have changed since the last triggering.

int BrickletJoystick::CALLBACK_POSITION_REACHED
<?php   void callback(int $x, int $y [, mixed $user_data])   ?>

This callback is triggered when the threshold as set by setPositionCallbackThreshold() is reached. The parameters are the position of the Joystick.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by setDebouncePeriod().

int BrickletJoystick::CALLBACK_ANALOG_VALUE_REACHED
<?php   void callback(int $x, int $y [, mixed $user_data])   ?>

This callback is triggered when the threshold as set by setAnalogValueCallbackThreshold() is reached. The parameters are the analog values of the Joystick.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by setDebouncePeriod().

int BrickletJoystick::CALLBACK_PRESSED
<?php   void callback([mixed $user_data])   ?>

This callback is triggered when the button is pressed.

int BrickletJoystick::CALLBACK_RELEASED
<?php   void callback([mixed $user_data])   ?>

This callback is triggered when the button is released.

Constants

int BrickletJoystick::DEVICE_IDENTIFIER

This constant is used to identify a Joystick Bricklet.

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

string BrickletJoystick::DEVICE_DISPLAY_NAME

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