Visual Basic .NET - Distance US Bricklet

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

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

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

        ' Get current distance value
        Dim distance As Integer = dus.GetDistanceValue()
        Console.WriteLine("Distance Value: " + distance.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 Distance US Bricklet

    ' Callback subroutine for distance value callback
    Sub DistanceCB(ByVal sender As BrickletDistanceUS, ByVal distance As Integer)
        Console.WriteLine("Distance Value: " + distance.ToString())
    End Sub

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

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

        ' Register distance value callback to subroutine DistanceCB
        AddHandler dus.DistanceCallback, AddressOf DistanceCB

        ' Set period for distance value callback to 0.2s (200ms)
        ' Note: The distance value callback is only called every 0.2 seconds
        '       if the distance value has changed since the last call!
        dus.SetDistanceCallbackPeriod(200)

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

Threshold

Download (ExampleThreshold.vb)

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Imports System
Imports Tinkerforge

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

    ' Callback subroutine for distance value reached callback
    Sub DistanceReachedCB(ByVal sender As BrickletDistanceUS, ByVal distance As Integer)
        Console.WriteLine("Distance Value: " + distance.ToString())
    End Sub

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim dus As New BrickletDistanceUS(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 10 seconds (10000ms)
        dus.SetDebouncePeriod(10000)

        ' Register distance value reached callback to subroutine DistanceReachedCB
        AddHandler dus.DistanceReachedCallback, AddressOf DistanceReachedCB

        ' Configure threshold for distance value "smaller than 200"
        dus.SetDistanceCallbackThreshold("<"C, 200, 0)

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

Creates an object with the unique device ID uid:

Dim distanceUS As New BrickletDistanceUS("YOUR_DEVICE_UID", ipcon)

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

Function BrickletDistanceUS.GetDistanceValue() As Integer

Returns the current distance value measured by the sensor. The value has a range of 0 to 4095. A small value corresponds to a small distance, a big value corresponds to a big distance. The relation between the measured distance value and the actual distance is affected by the 5V supply voltage (deviations in the supply voltage result in deviations in the distance values) and is non-linear (resolution is bigger at close range).

If you want to get the distance value periodically, it is recommended to use the DistanceCallback callback and set the period with SetDistanceCallbackPeriod().

Advanced Functions

Sub BrickletDistanceUS.SetMovingAverage(ByVal average As Byte)

Sets the length of a moving averaging for the distance value.

Setting the length to 0 will turn the averaging completely off. With less averaging, there is more noise on the data.

The range for the averaging is 0-100.

The default value is 20.

Function BrickletDistanceUS.GetMovingAverage() As Byte

Returns the length moving average as set by SetMovingAverage().

Function BrickletDistanceUS.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 BrickletDistanceUS.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 BrickletDistanceUS.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:

  • BrickletDistanceUS.FUNCTION_SET_DISTANCE_CALLBACK_PERIOD = 2
  • BrickletDistanceUS.FUNCTION_SET_DISTANCE_CALLBACK_THRESHOLD = 4
  • BrickletDistanceUS.FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletDistanceUS.FUNCTION_SET_MOVING_AVERAGE = 10
Sub BrickletDistanceUS.SetResponseExpectedAll(ByVal responseExpected As Boolean)

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

Sub BrickletDistanceUS.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 BrickletDistanceUS.SetDistanceCallbackPeriod(ByVal period As Long)

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

Der DistanceCallback callback is only triggered if the distance value has changed since the last triggering.

The default value is 0.

Function BrickletDistanceUS.GetDistanceCallbackPeriod() As Long

Returns the period as set by SetDistanceCallbackPeriod().

Sub BrickletDistanceUS.SetDistanceCallbackThreshold(ByVal option As Char, ByVal min As Integer, ByVal max As Integer)

Sets the thresholds for the DistanceReachedCallback callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the distance value is outside the min and max values
'i' Callback is triggered when the distance value is inside the min and max values
'<' Callback is triggered when the distance value is smaller than the min value (max is ignored)
'>' Callback is triggered when the distance 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:

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

Returns the threshold as set by SetDistanceCallbackThreshold().

The following constants are available for this function:

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

AddHandler distanceUS.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 BrickletDistanceUS.DistanceCallback(ByVal sender As BrickletDistanceUS, ByVal distance As Integer)

This callback is triggered periodically with the period that is set by SetDistanceCallbackPeriod(). The parameter is the distance value of the sensor.

The DistanceCallback callback is only triggered if the distance value has changed since the last triggering.

Event BrickletDistanceUS.DistanceReachedCallback(ByVal sender As BrickletDistanceUS, ByVal distance As Integer)

This callback is triggered when the threshold as set by SetDistanceCallbackThreshold() is reached. The parameter is the distance value of the sensor.

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

Constants

Const BrickletDistanceUS.DEVICE_IDENTIFIER

This constant is used to identify a Distance US 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 BrickletDistanceUS.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Distance US Bricklet.