Visual Basic .NET - Dual Button Bricklet

This is the description of the Visual Basic .NET 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 Visual Basic .NET API bindings is part of their general description.

Examples

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

Callback

Download (ExampleCallback.vb)

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Imports System
Imports Tinkerforge

Module ExampleCallback
    Const HOST As String = "localhost"
    Const PORT As Integer = 4223
    Const UID As String = "XYZ" ' Change XYZ to the UID of your Dual Button Bricklet

    ' Callback subroutine for state changed callback
    Sub StateChangedCB(ByVal sender As BrickletDualButton, ByVal buttonL As Byte, _
                       ByVal buttonR As Byte, ByVal ledL As Byte, ByVal ledR As Byte)
        If buttonL = BrickletDualButton.BUTTON_STATE_PRESSED Then
            Console.WriteLine("Left Button: Pressed")
        Else If buttonL = BrickletDualButton.BUTTON_STATE_RELEASED Then
            Console.WriteLine("Left Button: Released")
        End If

        If buttonR = BrickletDualButton.BUTTON_STATE_PRESSED Then
            Console.WriteLine("Right Button: Pressed")
        Else If buttonR = BrickletDualButton.BUTTON_STATE_RELEASED Then
            Console.WriteLine("Right Button: Released")
        End If

        Console.WriteLine("")
    End Sub

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim db As 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 subroutine StateChangedCB
        AddHandler db.StateChangedCallback, AddressOf StateChangedCB

        Console.WriteLine("Press key to exit")
        Console.ReadLine()
        ipcon.Disconnect()
    End Sub
End Module

API

Since Visual Basic .NET does not support multiple return values directly, we use the ByRef keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.

Basic Functions

Class BrickletDualButton(ByVal uid As String, ByVal ipcon As IPConnection)

Creates an object with the unique device ID uid:

Dim dualButton As New BrickletDualButton("YOUR_DEVICE_UID", ipcon)

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

Sub BrickletDualButton.SetLEDState(ByVal ledL As Byte, ByVal ledR As Byte)

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
Sub BrickletDualButton.GetLEDState(ByRef ledL As Byte, ByRef ledR As Byte)

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
Sub BrickletDualButton.GetButtonState(ByRef buttonL As Byte, ByRef buttonR As Byte)

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

Sub BrickletDualButton.SetSelectedLEDState(ByVal led As Byte, ByVal state As Byte)

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
Function BrickletDualButton.GetAPIVersion() As Byte()

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.

Function BrickletDualButton.GetResponseExpected(ByVal functionId As Byte) As 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.

Sub BrickletDualButton.SetResponseExpected(ByVal functionId As Byte, ByVal responseExpected As 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
Sub BrickletDualButton.SetResponseExpectedAll(ByVal responseExpected As Boolean)

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

Sub BrickletDualButton.GetIdentity(ByRef uid As String, ByRef connectedUid As String, ByRef position As Char, ByRef hardwareVersion() As Byte, ByRef firmwareVersion() As Byte, ByRef deviceIdentifier As Integer)

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.

Callbacks

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

Sub MyCallback(ByVal sender As BrickletDualButton, ByVal value As Short)
    Console.WriteLine("Value: {0}", value)
End Sub

AddHandler dualButton.ExampleCallback, AddressOf MyCallback

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 BrickletDualButton.StateChangedCallback(ByVal sender As BrickletDualButton, ByVal buttonL As Byte, ByVal buttonR As Byte, ByVal ledL As Byte, ByVal ledR As Byte)

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

Const BrickletDualButton.DEVICE_IDENTIFIER

This constant is used to identify a Dual Button Bricklet.

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

Const BrickletDualButton.DEVICE_DISPLAY_NAME

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