Visual Basic .NET - LED Strip Bricklet – Tinkerforge

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# Visual Basic .NET - LED Strip Bricklet

This is the description of the Visual Basic .NET API bindings for the LED Strip Bricklet. General information and technical specifications for the LED Strip 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 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 ledStrip As New BrickletLEDStrip(UID, ipcon) ' Create device object

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

            Dim r() As Byte = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
            Dim g() As Byte = {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0}
            Dim b() As Byte = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
            ledStrip.SetRGBValues(0, 10, r, g, b)

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

### Callback

Download (ExampleCallback.vb)

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    Imports Tinkerforge

    Module ExampleCallback
        Const HOST As String = "localhost"
        Const PORT As Integer = 4223
        Const UID As String = "XYZ" ' Change to your UID
        Const NUM_LEDS As Integer = 16

        Dim rIndex As Integer = 0
        Dim r() As Byte = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
        Dim g() As Byte = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
        Dim b() As Byte = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}

        ' Frame rendered callback, is called when a new frame was rendered
        ' We increase the index of one blue LED with every frame
        Sub FrameRenderedCB(ByVal sender As BrickletLEDStrip, ByVal length As Integer)
            b(rIndex) = 0
            If rIndex = NUM_LEDS-1 Then
                rIndex = 0
            Else
                rIndex = rIndex + 1
            End If
            b(rIndex) = 255

            ' Set new data for next render cycle
            sender.SetRGBValues(0, NUM_LEDS, r, g, b)
        End Sub

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

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

            ' Set frame duration to 50ms (20 frames per second)
            ledStrip.SetFrameDuration(50)

            ' Register frame rendered callback to function FrameRenderedCB
            AddHandler ledStrip.FrameRendered, AddressOf FrameRenderedCB

            ' Set initial rgb values to get started
            ledStrip.SetRGBValues(0, NUM_LEDS, r, g, b)

            System.Console.WriteLine("Press key to exit")
            System.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 `BrickletLEDStrip`(ByVal uid As String, ByVal ipcon As IPConnection)

  Creates an object with the unique device ID `uid`:

      Dim ledStrip As New BrickletLEDStrip("YOUR_DEVICE_UID", ipcon)

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

Sub `BrickletLEDStrip.``SetRGBValues`(ByVal index As Integer, ByVal length As Byte, ByVal r() As Byte, ByVal g() As Byte, ByVal b() As Byte)

  Sets the rgb values for the LEDs with the given length starting from index.

  The maximum length is 16, the index goes from 0 to 319 and the rgb values have 8 bits each.

  Example: If you set

  - index to 5,
  - length to 3,
  - r to [255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
  - g to [0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] and
  - b to [0, 0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

  the LED with index 5 will be red, 6 will be green and 7 will be blue.

  Note

  Depending on the LED circuitry colors can be permuted.

  The colors will be transfered to actual LEDs when the next frame duration ends, see `SetFrameDuration()`.

  Generic approach:

  - Set the frame duration to a value that represents the number of frames per second you want to achieve.
  - Set all of the LED colors for one frame.
  - Wait for the `FrameRendered` callback.
  - Set all of the LED colors for next frame.
  - Wait for the `FrameRendered` callback.
  - and so on.

  This approach ensures that you can change the LED colors with a fixed frame rate.

  The actual number of controllable LEDs depends on the number of free Bricklet ports. See here for more information. A call of `SetRGBValues()` with index + length above the bounds is ignored completely.

Sub `BrickletLEDStrip.``GetRGBValues`(ByVal index As Integer, ByVal length As Byte, ByRef r() As Byte, ByRef g() As Byte, ByRef b() As Byte)

  Returns the rgb with the given length starting from the given index.

  The values are the last values that were set by `SetRGBValues()`.

Sub `BrickletLEDStrip.``SetFrameDuration`(ByVal duration As Integer)

  Sets the frame duration in ms.

  Example: If you want to achieve 20 frames per second, you should set the frame duration to 50ms (50ms * 20 = 1 second).

  For an explanation of the general approach see `SetRGBValues()`.

  Default value: 100ms (10 frames per second).

Function `BrickletLEDStrip.``GetFrameDuration`() As Integer

  Returns the frame duration as set by `SetFrameDuration()`.

Function `BrickletLEDStrip.``GetSupplyVoltage`() As Integer

  Returns the current supply voltage of the LEDs. The voltage is given in mV.

Sub `BrickletLEDStrip.``SetClockFrequency`(ByVal frequency As Long)

  Sets the frequency of the clock in Hz. The range is 10000Hz (10kHz) up to 2000000Hz (2MHz).

  The Bricklet will choose the nearest achievable frequency, which may be off by a few Hz. You can get the exact frequency that is used by calling `GetClockFrequency()`.

  If you have problems with flickering LEDs, they may be bits flipping. You can fix this by either making the connection between the LEDs and the Bricklet shorter or by reducing the frequency.

  With a decreasing frequency your maximum frames per second will decrease too.

  The default value is 1.66MHz.

  Note

  The frequency in firmware version 2.0.0 is fixed at 2MHz.

  New in version 2.0.1 (Plugin).

Function `BrickletLEDStrip.``GetClockFrequency`() As Long

  Returns the currently used clock frequency as set by `SetClockFrequency()`.

  New in version 2.0.1 (Plugin).

Sub `BrickletLEDStrip.``SetChipType`(ByVal chip As Integer)

  Sets the type of the led driver chip. We currently support the chips

  - WS2801 (`chip` = 2801),
  - WS2811 (`chip` = 2811) and
  - WS2812 (`chip` = 2812).

  The WS2812 is sometimes also called "NeoPixel", a name coined by Adafruit.

  The default value is WS2801 (`chip` = 2801).

  The following constants are available for this function:

  - BrickletLEDStrip.CHIP_TYPE_WS2801 = 2801
  - BrickletLEDStrip.CHIP_TYPE_WS2811 = 2811
  - BrickletLEDStrip.CHIP_TYPE_WS2812 = 2812

  New in version 2.0.2 (Plugin).

Function `BrickletLEDStrip.``GetChipType`() As Integer

  Returns the currently used chip type as set by `SetChipType()`.

  The following constants are available for this function:

  - BrickletLEDStrip.CHIP_TYPE_WS2801 = 2801
  - BrickletLEDStrip.CHIP_TYPE_WS2811 = 2811
  - BrickletLEDStrip.CHIP_TYPE_WS2812 = 2812

  New in version 2.0.2 (Plugin).

### Advanced Functions

Function `BrickletLEDStrip.``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 `BrickletLEDStrip.``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 `BrickletLEDStrip.``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 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:

  - BrickletLEDStrip.FUNCTION_SET_RGB_VALUES = 1
  - BrickletLEDStrip.FUNCTION_SET_FRAME_DURATION = 3
  - BrickletLEDStrip.FUNCTION_SET_CLOCK_FREQUENCY = 7
  - BrickletLEDStrip.FUNCTION_SET_CHIP_TYPE = 9

Sub `BrickletLEDStrip.``SetResponseExpectedAll`(ByVal responseExpected As Boolean)

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

Sub `BrickletLEDStrip.``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 Callback(ByVal sender As BrickletLEDStrip, ByVal value As Short)
>         Console.WriteLine("Value: {0}", value)
>     End Sub

>     AddHandler ledStrip.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.

Event `BrickletLEDStrip.``FrameRendered`(ByVal sender As BrickletLEDStrip, ByVal length As Integer)

  This callback is triggered directly after a new frame is rendered.

  You should send the data for the next frame directly after this callback was triggered.

  For an explanation of the general approach see `SetRGBValues()`.

### Constants

Const `BrickletLEDStrip.``DEVICE_IDENTIFIER`

  This constant is used to identify a LED Strip 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.

The content of this page is licensed under Creative Commons Attribution 3.0 Unported License.