JavaScript - Dual Button Bricklet

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

Examples

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

Callback (Node.js)

Download (ExampleCallback.js)

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var Tinkerforge = require('tinkerforge');

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

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

ipcon.connect(HOST, PORT,
    function (error) {
        console.log('Error: ' + error);
    }
); // Connect to brickd
// Don't use device before ipcon is connected

// Register state changed callback
db.on(Tinkerforge.BrickletDualButton.CALLBACK_STATE_CHANGED,
    // Callback function for state changed callback
    function (buttonL, buttonR, ledL, ledR) {
        if(buttonL === Tinkerforge.BrickletDualButton.BUTTON_STATE_PRESSED) {
            console.log('Left Button: Pressed');
        }
        else if(buttonL === Tinkerforge.BrickletDualButton.BUTTON_STATE_RELEASED) {
            console.log('Left Button: Released');
        }

        if(buttonR === Tinkerforge.BrickletDualButton.BUTTON_STATE_PRESSED) {
            console.log('Right Button: Pressed');
        }
        else if(buttonR === Tinkerforge.BrickletDualButton.BUTTON_STATE_RELEASED) {
            console.log('Right Button: Released');
        }

        console.log();
    }
);

console.log('Press key to exit');
process.stdin.on('data',
    function (data) {
        ipcon.disconnect();
        process.exit(0);
    }
);

Callback (HTML)

Download (ExampleCallback.html), Test (ExampleCallback.html)

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<!DOCTYPE html>
<html>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <head>
        <title>Tinkerforge | JavaScript Example</title>
    </head>
    <body>
        <div style="text-align:center;">
            <h1>Dual Button Bricklet Callback Example</h1>
            <p>
                <input value="localhost" id="host" type="text" size="20">:
                <input value="4280" id="port" type="text" size="5">,
                <input value="uid" id="uid" type="text" size="5">
                <input value="Start Example" id="start" type="button" onclick="startExample();">
            </p>
            <p>
                <textarea readonly id="text" cols="80" rows="24" style="resize:none;"
                          >Press "Start Example" to begin ...</textarea>
            </p>
        </div>
        <script src="./Tinkerforge.js" type='text/javascript'></script>
        <script type='text/javascript'>
            var ipcon;
            var textArea = document.getElementById("text");
            function startExample() {
                textArea.value = "";
                var HOST = document.getElementById("host").value;
                var PORT = parseInt(document.getElementById("port").value);
                var UID = document.getElementById("uid").value;
                if(ipcon !== undefined) {
                    ipcon.disconnect();
                }
                ipcon = new Tinkerforge.IPConnection(); // Create IP connection
                var db = new Tinkerforge.BrickletDualButton(UID, ipcon); // Create device object
                ipcon.connect(HOST, PORT,
                    function(error) {
                        textArea.value += 'Error: ' + error + '\n';
                    }
                ); // Connect to brickd
                // Don't use device before ipcon is connected

                // Register state changed callback
                db.on(Tinkerforge.BrickletDualButton.CALLBACK_STATE_CHANGED,
                    // Callback function for state changed callback
                    function (buttonL, buttonR, ledL, ledR) {
                        if(buttonL === Tinkerforge.BrickletDualButton.BUTTON_STATE_PRESSED) {
                            textArea.value += 'Left Button: Pressed\n';
                        }
                        else if(buttonL === Tinkerforge.BrickletDualButton.BUTTON_STATE_RELEASED) {
                            textArea.value += 'Left Button: Released\n';
                        }

                        if(buttonR === Tinkerforge.BrickletDualButton.BUTTON_STATE_PRESSED) {
                            textArea.value += 'Right Button: Pressed\n';
                        }
                        else if(buttonR === Tinkerforge.BrickletDualButton.BUTTON_STATE_RELEASED) {
                            textArea.value += 'Right Button: Released\n';
                        }

                        textArea.value += '\n';
                        textArea.scrollTop = textArea.scrollHeight;
                    }
                );
            }
        </script>
    </body>
</html>

API

Generally, every method of the JavaScript bindings can take two optional parameters, returnCallback and errorCallback. These are two user defined callback functions. The returnCallback is called with the return values as parameters, if the method returns something. The errorCallback is called with an error code in case of an error. The error code can be one of the following values:

  • IPConnection.ERROR_ALREADY_CONNECTED = 11
  • IPConnection.ERROR_NOT_CONNECTED = 12
  • IPConnection.ERROR_CONNECT_FAILED = 13
  • IPConnection.ERROR_INVALID_FUNCTION_ID = 21
  • IPConnection.ERROR_TIMEOUT = 31
  • IPConnection.ERROR_INVALID_PARAMETER = 41
  • IPConnection.ERROR_FUNCTION_NOT_SUPPORTED = 42
  • IPConnection.ERROR_UNKNOWN_ERROR = 43

The namespace for the JavaScript bindings is Tinkerforge.*.

Basic Functions

new BrickletDualButton(uid, ipcon)
Parameters:
  • uid -- string
  • ipcon -- IPConnection

Creates an object with the unique device ID uid:

var dualButton = new BrickletDualButton("YOUR_DEVICE_UID", ipcon);

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

BrickletDualButton.setLEDState(ledL, ledR[, returnCallback][, errorCallback])
Parameters:
  • ledL -- int
  • ledR -- int
Callback:

undefined

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
BrickletDualButton.getLEDState([returnCallback][, errorCallback])
Callback:
  • ledL -- int
  • ledR -- int

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
BrickletDualButton.getButtonState([returnCallback][, errorCallback])
Callback:
  • buttonL -- int
  • buttonR -- int

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

Advanced Functions

BrickletDualButton.setSelectedLEDState(led, state[, returnCallback][, errorCallback])
Parameters:
  • led -- int
  • state -- int
Callback:

undefined

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
BrickletDualButton.getAPIVersion()
Return type:[int, int, int]

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.

BrickletDualButton.getResponseExpected(functionId[, errorCallback])
Parameters:
  • functionId -- int
Return type:

boolean

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.

BrickletDualButton.setResponseExpected(functionId, responseExpected[, errorCallback])
Parameters:
  • functionId -- int
  • responseExpected -- boolean

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
BrickletDualButton.setResponseExpectedAll(responseExpected)
Parameters:
  • responseExpected -- boolean

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

BrickletDualButton.getIdentity([returnCallback][, errorCallback])
Callback:
  • uid -- string
  • connectedUid -- string
  • position -- char
  • hardwareVersion -- [int, int, int]
  • firmwareVersion -- [int, int, int]
  • deviceIdentifier -- int

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

BrickletDualButton.on(callback_id, function)
Parameters:
  • callback_id -- int
  • function -- function

Registers the given function with the given callback_id.

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 on() function of the device object. The first parameter is the callback ID and the second parameter the callback function:

dualButton.on(BrickletDualButton.CALLBACK_EXAMPLE,
    function (param) {
        console.log(param);
    }
);

The available constants with inherent number and 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.

BrickletDualButton.CALLBACK_STATE_CHANGED
Parameters:
  • buttonL -- int
  • buttonR -- int
  • ledL -- int
  • ledR -- int

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

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 device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletDualButton.DEVICE_DISPLAY_NAME

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