PHP - Dual Button Bricklet

This is the description of the PHP API bindings for the Dual Button Bricklet. General information and technical specifications for the Dual Button 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).

Callback

Download (ExampleCallback.php)

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<?php

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

use Tinkerforge\IPConnection;
use Tinkerforge\BrickletDualButton;

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

// Callback function for state changed callback
function cb_stateChanged($button_l, $button_r, $led_l, $led_r)
{
    if ($button_l == BrickletDualButton::BUTTON_STATE_PRESSED) {
        echo "Left Button: Pressed\n";
    } elseif ($button_l == BrickletDualButton::BUTTON_STATE_RELEASED) {
        echo "Left Button: Released\n";
    }

    if ($button_r == BrickletDualButton::BUTTON_STATE_PRESSED) {
        echo "Right Button: Pressed\n";
    } elseif ($button_r == BrickletDualButton::BUTTON_STATE_RELEASED) {
        echo "Right Button: Released\n";
    }

    echo "\n";
}

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

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

// Register state changed callback to function cb_stateChanged
$db->registerCallback(BrickletDualButton::CALLBACK_STATE_CHANGED, 'cb_stateChanged');

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 BrickletDualButton(string $uid, IPConnection $ipcon)

Creates an object with the unique device ID $uid:

<?php   $dual_button = new BrickletDualButton('YOUR_DEVICE_UID', $ipcon);   ?>

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

void BrickletDualButton::setLEDState(int $led_l, int $led_r)

Sets the state of the LEDs. Possible states are:

  • 0 = AutoToggleOn: Enables auto toggle with initially enabled LED.
  • 1 = AutoToggleOff: Activates auto toggle with initially disabled LED.
  • 2 = On: Enables LED (auto toggle is disabled).
  • 3 = Off: Disables LED (auto toggle is disabled).

In auto toggle mode the LED is toggled automatically at each press of a button.

If you just want to set one of the LEDs and don't know the current state of the other LED, you can get the state with getLEDState() or you can use setSelectedLEDState().

The default value is (1, 1).

The following constants are available for this function:

  • BrickletDualButton::LED_STATE_AUTO_TOGGLE_ON = 0
  • BrickletDualButton::LED_STATE_AUTO_TOGGLE_OFF = 1
  • BrickletDualButton::LED_STATE_ON = 2
  • BrickletDualButton::LED_STATE_OFF = 3
array BrickletDualButton::getLEDState()

Returns the current state of the LEDs, as set by setLEDState().

The following constants are available for this function:

  • BrickletDualButton::LED_STATE_AUTO_TOGGLE_ON = 0
  • BrickletDualButton::LED_STATE_AUTO_TOGGLE_OFF = 1
  • BrickletDualButton::LED_STATE_ON = 2
  • BrickletDualButton::LED_STATE_OFF = 3

The returned array has the keys led_l and led_r.

array BrickletDualButton::getButtonState()

Returns the current state for both buttons. Possible states are:

  • 0 = pressed
  • 1 = released

The following constants are available for this function:

  • BrickletDualButton::BUTTON_STATE_PRESSED = 0
  • BrickletDualButton::BUTTON_STATE_RELEASED = 1

The returned array has the keys button_l and button_r.

Advanced Functions

void BrickletDualButton::setSelectedLEDState(int $led, int $state)

Sets the state of the selected LED (0 or 1).

The other LED remains untouched.

The following constants are available for this function:

  • BrickletDualButton::LED_LEFT = 0
  • BrickletDualButton::LED_RIGHT = 1
  • BrickletDualButton::LED_STATE_AUTO_TOGGLE_ON = 0
  • BrickletDualButton::LED_STATE_AUTO_TOGGLE_OFF = 1
  • BrickletDualButton::LED_STATE_ON = 2
  • BrickletDualButton::LED_STATE_OFF = 3
array BrickletDualButton::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 BrickletDualButton::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 BrickletDualButton::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:

  • BrickletDualButton::FUNCTION_SET_LED_STATE = 1
  • BrickletDualButton::FUNCTION_SET_SELECTED_LED_STATE = 5
void BrickletDualButton::setResponseExpectedAll(bool $response_expected)

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

array BrickletDualButton::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 BrickletDualButton::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.

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";
}

$dual_button->registerCallback(BrickletDualButton::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 BrickletDualButton::CALLBACK_STATE_CHANGED
<?php   void callback(int $button_l, int $button_r, int $led_l, int $led_r [, mixed $user_data])   ?>

This callback is called whenever a button is pressed.

Possible states for buttons are:

  • 0 = pressed
  • 1 = released

Possible states for LEDs are:

  • 0 = AutoToggleOn: Auto toggle enabled and LED on.
  • 1 = AutoToggleOff: Auto toggle enabled and LED off.
  • 2 = On: LED on (auto toggle is disabled).
  • 3 = Off: LED off (auto toggle is disabled).

The following constants are available for this function:

  • BrickletDualButton::BUTTON_STATE_PRESSED = 0
  • BrickletDualButton::BUTTON_STATE_RELEASED = 1
  • BrickletDualButton::LED_STATE_AUTO_TOGGLE_ON = 0
  • BrickletDualButton::LED_STATE_AUTO_TOGGLE_OFF = 1
  • BrickletDualButton::LED_STATE_ON = 2
  • BrickletDualButton::LED_STATE_OFF = 3

Constants

int BrickletDualButton::DEVICE_IDENTIFIER

This constant is used to identify a Dual Button 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 BrickletDualButton::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Dual Button Bricklet.