Visual Basic .NET - Linear Poti Bricklet

This is the description of the Visual Basic .NET API bindings for the Linear Poti Bricklet. General information and technical specifications for the Linear Poti 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 Linear Poti Bricklet

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim lp As New BrickletLinearPoti(UID, ipcon) ' Create device object

        ipcon.Connect(HOST, PORT) ' Connect to brickd
        ' Don't use device before ipcon is connected

        ' Get current position
        Dim position As Integer = lp.GetPosition()
        Console.WriteLine("Position: " + position.ToString()) ' Range: 0 to 100

        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 Linear Poti Bricklet

    ' Callback subroutine for position callback
    Sub PositionCB(ByVal sender As BrickletLinearPoti, ByVal position As Integer)
        Console.WriteLine("Position: " + position.ToString()) ' Range: 0 to 100
    End Sub

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim lp As New BrickletLinearPoti(UID, ipcon) ' Create device object

        ipcon.Connect(HOST, PORT) ' Connect to brickd
        ' Don't use device before ipcon is connected

        ' Register position callback to subroutine PositionCB
        AddHandler lp.PositionCallback, AddressOf PositionCB

        ' Set period for position callback to 0.05s (50ms)
        ' Note: The position callback is only called every 0.05 seconds
        '       if the position has changed since the last call!
        lp.SetPositionCallbackPeriod(50)

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

Creates an object with the unique device ID uid:

Dim linearPoti As New BrickletLinearPoti("YOUR_DEVICE_UID", ipcon)

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

Function BrickletLinearPoti.GetPosition() As Integer

Returns the position of the linear potentiometer. The value is between 0 (slider down) and 100 (slider up).

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

Advanced Functions

Function BrickletLinearPoti.GetAnalogValue() As Integer

Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.

Note

The value returned by GetPosition() is 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 value periodically, it is recommended to use the AnalogValueCallback callback and set the period with SetAnalogValueCallbackPeriod().

Function BrickletLinearPoti.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 BrickletLinearPoti.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 BrickletLinearPoti.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:

  • BrickletLinearPoti.FUNCTION_SET_POSITION_CALLBACK_PERIOD = 3
  • BrickletLinearPoti.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BrickletLinearPoti.FUNCTION_SET_POSITION_CALLBACK_THRESHOLD = 7
  • BrickletLinearPoti.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BrickletLinearPoti.FUNCTION_SET_DEBOUNCE_PERIOD = 11
Sub BrickletLinearPoti.SetResponseExpectedAll(ByVal responseExpected As Boolean)

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

Sub BrickletLinearPoti.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 BrickletLinearPoti.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 BrickletLinearPoti.GetPositionCallbackPeriod() As Long

Returns the period as set by SetPositionCallbackPeriod().

Sub BrickletLinearPoti.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 value has changed since the last triggering.

The default value is 0.

Function BrickletLinearPoti.GetAnalogValueCallbackPeriod() As Long

Returns the period as set by SetAnalogValueCallbackPeriod().

Sub BrickletLinearPoti.SetPositionCallbackThreshold(ByVal option As Char, ByVal min As Integer, ByVal max As Integer)

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 value (max is ignored)
'>' Callback is triggered when the position is greater than the min value (max is ignored)

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

The following constants are available for this function:

  • BrickletLinearPoti.THRESHOLD_OPTION_OFF = "x"C
  • BrickletLinearPoti.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletLinearPoti.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletLinearPoti.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletLinearPoti.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletLinearPoti.GetPositionCallbackThreshold(ByRef option As Char, ByRef min As Integer, ByRef max As Integer)

Returns the threshold as set by SetPositionCallbackThreshold().

The following constants are available for this function:

  • BrickletLinearPoti.THRESHOLD_OPTION_OFF = "x"C
  • BrickletLinearPoti.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletLinearPoti.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletLinearPoti.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletLinearPoti.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletLinearPoti.SetAnalogValueCallbackThreshold(ByVal option As Char, ByVal min As Integer, ByVal max 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 value is outside the min and max values
'i' Callback is triggered when the analog value is inside the min and max values
'<' Callback is triggered when the analog value is smaller than the min value (max is ignored)
'>' Callback is triggered when the analog value is greater than the min value (max is ignored)

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

The following constants are available for this function:

  • BrickletLinearPoti.THRESHOLD_OPTION_OFF = "x"C
  • BrickletLinearPoti.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletLinearPoti.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletLinearPoti.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletLinearPoti.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletLinearPoti.GetAnalogValueCallbackThreshold(ByRef option As Char, ByRef min As Integer, ByRef max As Integer)

Returns the threshold as set by SetAnalogValueCallbackThreshold().

The following constants are available for this function:

  • BrickletLinearPoti.THRESHOLD_OPTION_OFF = "x"C
  • BrickletLinearPoti.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletLinearPoti.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletLinearPoti.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletLinearPoti.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletLinearPoti.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 BrickletLinearPoti.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 BrickletLinearPoti, ByVal value As Short)
    Console.WriteLine("Value: {0}", value)
End Sub

AddHandler linearPoti.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 BrickletLinearPoti.PositionCallback(ByVal sender As BrickletLinearPoti, ByVal position As Integer)

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

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

Event BrickletLinearPoti.AnalogValueCallback(ByVal sender As BrickletLinearPoti, ByVal value As Integer)

This callback is triggered periodically with the period that is set by SetAnalogValueCallbackPeriod(). The parameter is the analog value of the Linear Potentiometer.

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

Event BrickletLinearPoti.PositionReachedCallback(ByVal sender As BrickletLinearPoti, ByVal position As Integer)

This callback is triggered when the threshold as set by SetPositionCallbackThreshold() is reached. The parameter is the position of the linear potentiometer.

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

Event BrickletLinearPoti.AnalogValueReachedCallback(ByVal sender As BrickletLinearPoti, ByVal value As Integer)

This callback is triggered when the threshold as set by SetAnalogValueCallbackThreshold() is reached. The parameter is the analog value of the linear potentiometer.

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

Constants

Const BrickletLinearPoti.DEVICE_IDENTIFIER

This constant is used to identify a Linear Poti 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 BrickletLinearPoti.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Linear Poti Bricklet.