Visual Basic .NET - Joystick Bricklet

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

Examples

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

Simple

Download (ExampleSimple.vb)

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Imports System
Imports Tinkerforge

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

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim j As 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
        Dim x, y As Short

        j.GetPosition(x, y)

        Console.WriteLine("Position [X]: " + x.ToString())
        Console.WriteLine("Position [Y]: " + y.ToString())

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

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 Joystick Bricklet

    ' Callback subroutine for pressed callback
    Sub PressedCB(ByVal sender As BrickletJoystick)
        Console.WriteLine("Pressed")
    End Sub

    ' Callback subroutine for released callback
    Sub ReleasedCB(ByVal sender As BrickletJoystick)
        Console.WriteLine("Released")
    End Sub

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim j As 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 subroutine PressedCB
        AddHandler j.PressedCallback, AddressOf PressedCB

        ' Register released callback to subroutine ReleasedCB
        AddHandler j.ReleasedCallback, AddressOf ReleasedCB

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

Find Borders

Download (ExampleFindBorders.vb)

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Imports System
Imports Tinkerforge

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

    ' Callback subroutine for position reached callback
    Sub PositionReachedCB(ByVal sender As BrickletJoystick, ByVal x As Short, _
                          ByVal y As Short)
        If y = 100 Then
            Console.WriteLine("Top")
        Else If y = -100 Then
            Console.WriteLine("Bottom")
        End If

        If x = 100 Then
            Console.WriteLine("Right")
        Else If x = -100 Then
            Console.WriteLine("Left")
        End If

        Console.WriteLine("")
    End Sub

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim j As 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 subroutine PositionReachedCB
        AddHandler j.PositionReachedCallback, AddressOf PositionReachedCB

        ' Configure threshold for position "outside of -99, -99 to 99, 99"
        j.SetPositionCallbackThreshold("o"C, -99, 99, -99, 99)

        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 BrickletJoystick(ByVal uid As String, ByVal ipcon As IPConnection)

Creates an object with the unique device ID uid:

Dim joystick As New BrickletJoystick("YOUR_DEVICE_UID", ipcon)

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

Sub BrickletJoystick.GetPosition(ByRef x As Short, ByRef y As Short)

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 PositionCallback callback and set the period with SetPositionCallbackPeriod().

Function BrickletJoystick.IsPressed() As Boolean

Returns true if the button is pressed and false otherwise.

It is recommended to use the PressedCallback and ReleasedCallback callbacks to handle the button.

Advanced Functions

Sub BrickletJoystick.GetAnalogValue(ByRef x As Integer, ByRef y As Integer)

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 AnalogValueCallback callback and set the period with SetAnalogValueCallbackPeriod().

Sub 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.

Function BrickletJoystick.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 BrickletJoystick.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 BrickletJoystick.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:

  • 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
Sub BrickletJoystick.SetResponseExpectedAll(ByVal responseExpected As Boolean)

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

Sub BrickletJoystick.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.

Callback Configuration Functions

Sub BrickletJoystick.SetPositionCallbackPeriod(ByVal period As Long)

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

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

The default value is 0.

Function BrickletJoystick.GetPositionCallbackPeriod() As Long

Returns the period as set by SetPositionCallbackPeriod().

Sub BrickletJoystick.SetAnalogValueCallbackPeriod(ByVal period As Long)

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

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

The default value is 0.

Function BrickletJoystick.GetAnalogValueCallbackPeriod() As Long

Returns the period as set by SetAnalogValueCallbackPeriod().

Sub BrickletJoystick.SetPositionCallbackThreshold(ByVal option As Char, ByVal minX As Short, ByVal maxX As Short, ByVal minY As Short, ByVal maxY As Short)

Sets the thresholds for the PositionReachedCallback 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"C
  • BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletJoystick.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletJoystick.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletJoystick.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletJoystick.GetPositionCallbackThreshold(ByRef option As Char, ByRef minX As Short, ByRef maxX As Short, ByRef minY As Short, ByRef maxY As Short)

Returns the threshold as set by SetPositionCallbackThreshold().

The following constants are available for this function:

  • BrickletJoystick.THRESHOLD_OPTION_OFF = "x"C
  • BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletJoystick.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletJoystick.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletJoystick.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletJoystick.SetAnalogValueCallbackThreshold(ByVal option As Char, ByVal minX As Integer, ByVal maxX As Integer, ByVal minY As Integer, ByVal maxY As Integer)

Sets the thresholds for the AnalogValueReachedCallback 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"C
  • BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletJoystick.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletJoystick.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletJoystick.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletJoystick.GetAnalogValueCallbackThreshold(ByRef option As Char, ByRef minX As Integer, ByRef maxX As Integer, ByRef minY As Integer, ByRef maxY As Integer)

Returns the threshold as set by SetAnalogValueCallbackThreshold().

The following constants are available for this function:

  • BrickletJoystick.THRESHOLD_OPTION_OFF = "x"C
  • BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletJoystick.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletJoystick.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletJoystick.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletJoystick.SetDebouncePeriod(ByVal debounce As Long)

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

Function BrickletJoystick.GetDebouncePeriod() As Long

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 by assigning a procedure to an callback property of the device object:

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

AddHandler joystick.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 BrickletJoystick.PositionCallback(ByVal sender As BrickletJoystick, ByVal x As Short, ByVal y As Short)

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

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

Event BrickletJoystick.AnalogValueCallback(ByVal sender As BrickletJoystick, ByVal x As Integer, ByVal y As Integer)

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

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

Event BrickletJoystick.PositionReachedCallback(ByVal sender As BrickletJoystick, ByVal x As Short, ByVal y As Short)

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().

Event BrickletJoystick.AnalogValueReachedCallback(ByVal sender As BrickletJoystick, ByVal x As Integer, ByVal y As Integer)

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().

Event BrickletJoystick.PressedCallback(ByVal sender As BrickletJoystick)

This callback is triggered when the button is pressed.

Event BrickletJoystick.ReleasedCallback(ByVal sender As BrickletJoystick)

This callback is triggered when the button is released.

Constants

Const BrickletJoystick.DEVICE_IDENTIFIER

This constant is used to identify a Joystick 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 BrickletJoystick.DEVICE_DISPLAY_NAME

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