This is the description of the Visual Basic .NET API bindings for the Line Bricklet. General information and technical specifications for the Line Bricklet are summarized in its hardware description.
An installation guide for the Visual Basic .NET API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | Imports Tinkerforge
Module ExampleSimple
Const HOST As String = "localhost"
Const PORT As Integer = 4223
Const UID As String = "XYZ" ' Change to your UID
Sub Main()
Dim ipcon As New IPConnection() ' Create IP connection
Dim line As New BrickletLine(UID, ipcon) ' Create device object
ipcon.Connect(HOST, PORT) ' Connect to brickd
' Don't use device before ipcon is connected
' Get current reflectivity
Dim reflectivity As Integer = line.GetReflectivity()
System.Console.WriteLine("Reflectivity: " + reflectivity.ToString())
System.Console.WriteLine("Press key to exit")
System.Console.ReadLine()
ipcon.Disconnect()
End Sub
End Module
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | Imports Tinkerforge
Module ExampleCallback
Const HOST As String = "localhost"
Const PORT As Integer = 4223
Const UID As String = "XYZ" ' Change to your UID
' Callback function for reflectivity
Sub ReflectivityCB(ByVal sender As BrickletLine, ByVal reflectivity As Integer)
System.Console.WriteLine("Reflectivity: " + reflectivity.ToString())
End Sub
Sub Main()
Dim ipcon As New IPConnection() ' Create IP connection
Dim line As New BrickletLine(UID, ipcon) ' Create device object
ipcon.Connect(HOST, PORT) ' Connect to brickd
' Don't use device before ipcon is connected
' Set Period for reflectivity callback to 1s (1000ms)
' Note: The reflectivity callback is only called every second if the
' reflectivity has changed since the last call!
line.SetReflectivityCallbackPeriod(1000)
' Register reflectivity callback to function ReflectivityCB
AddHandler line.Reflectivity, AddressOf ReflectivityCB
System.Console.WriteLine("Press key to exit")
System.Console.ReadLine()
ipcon.Disconnect()
End Sub
End Module
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Download (ExampleThreshold.vb)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | Imports Tinkerforge
Module ExampleThreshold
Const HOST As String = "localhost"
Const PORT As Integer = 4223
Const UID As String = "XYZ" ' Change to your UID
' Callback for reflectivity greater than 2000
Sub ReachedCB(ByVal sender As BrickletLine, ByVal reflectivity As Integer)
System.Console.WriteLine("Reflectivity: " + reflectivity.ToString())
End Sub
Sub Main()
Dim ipcon As New IPConnection() ' Create IP connection
Dim line As New BrickletLine(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 1 second (1000ms)
line.SetDebouncePeriod(1000)
' Register threshold reached callback to function ReachedCB
AddHandler line.ReflectivityReached, AddressOf ReachedCB
' Configure threshold for "greater than 2000"
line.SetReflectivityCallbackThreshold(">"C, 2000, 0)
System.Console.WriteLine("Press key to exit")
System.Console.ReadLine()
ipcon.Disconnect()
End Sub
End Module
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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.
Creates an object with the unique device ID uid:
Dim line As New BrickletLine("YOUR_DEVICE_UID", ipcon)
This object can then be used after the IP Connection is connected (see examples above).
Returns the currently measured reflectivity. The reflectivity is a value between 0 (not reflective) and 4095 (very reflective).
Usually black has a low reflectivity while white has a high reflectivity.
If you want to get the reflectivity periodically, it is recommended to use the callback Reflectivity and set the period with SetReflectivityCallbackPeriod().
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.
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.
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 and callbacks it is always disabled.
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:
Changes the response expected flag for all setter and callback configuration functions of this device at once.
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.
Sets the period in ms with which the Reflectivity callback is triggered periodically. A value of 0 turns the callback off.
Reflectivity is only triggered if the reflectivity has changed since the last triggering.
The default value is 0.
Returns the period as set by SetReflectivityCallbackPeriod().
Sets the thresholds for the ReflectivityReached callback.
The following options are possible:
Option | Description |
---|---|
'x' | Callback is turned off |
'o' | Callback is triggered when the reflectivity is outside the min and max values |
'i' | Callback is triggered when the reflectivity is inside the min and max values |
'<' | Callback is triggered when the reflectivity is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the reflectivity is greater than the min value (max is ignored) |
The default value is ('x', 0, 0).
The following constants are available for this function:
Returns the threshold as set by SetReflectivityCallbackThreshold().
The following constants are available for this function:
Sets the period in ms with which the threshold callback
is triggered, if the threshold
keeps being reached.
The default value is 100.
Returns the debounce period as set by SetDebouncePeriod().
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 Callback(ByVal sender As BrickletLine, ByVal value As Short) Console.WriteLine("Value: {0}", value) End Sub AddHandler line.Example, AddressOf Callback
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.
This callback is triggered periodically with the period that is set by SetReflectivityCallbackPeriod(). The parameter is the reflectivity of the sensor.
Reflectivity is only triggered if the reflectivity has changed since the last triggering.
This callback is triggered when the threshold as set by SetReflectivityCallbackThreshold() is reached. The parameter is the reflectivity of the sensor.
If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod().
This constant is used to identify a Line 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.