Visual Basic .NET - CO2 Bricklet

This is the description of the Visual Basic .NET API bindings for the CO2 Bricklet. General information and technical specifications for the CO2 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 CO2 Bricklet

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim co2 As New BrickletCO2(UID, ipcon) ' Create device object

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

        ' Get current CO2 concentration
        Dim co2Concentration As Integer = co2.GetCO2Concentration()
        Console.WriteLine("CO2 Concentration: " + co2Concentration.ToString() + " ppm")

        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 CO2 Bricklet

    ' Callback subroutine for CO2 concentration callback
    Sub CO2ConcentrationCB(ByVal sender As BrickletCO2, _
                           ByVal co2Concentration As Integer)
        Console.WriteLine("CO2 Concentration: " + co2Concentration.ToString() + " ppm")
    End Sub

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim co2 As New BrickletCO2(UID, ipcon) ' Create device object

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

        ' Register CO2 concentration callback to subroutine CO2ConcentrationCB
        AddHandler co2.CO2ConcentrationCallback, AddressOf CO2ConcentrationCB

        ' Set period for CO2 concentration callback to 1s (1000ms)
        ' Note: The CO2 concentration callback is only called every second
        '       if the CO2 concentration has changed since the last call!
        co2.SetCO2ConcentrationCallbackPeriod(1000)

        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 CO2 Bricklet

    ' Callback subroutine for CO2 concentration reached callback
    Sub CO2ConcentrationReachedCB(ByVal sender As BrickletCO2, _
                                  ByVal co2Concentration As Integer)
        Console.WriteLine("CO2 Concentration: " + co2Concentration.ToString() + " ppm")
    End Sub

    Sub Main()
        Dim ipcon As New IPConnection() ' Create IP connection
        Dim co2 As New BrickletCO2(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)
        co2.SetDebouncePeriod(10000)

        ' Register CO2 concentration reached callback to subroutine
        ' CO2ConcentrationReachedCB
        AddHandler co2.CO2ConcentrationReachedCallback, _
                   AddressOf CO2ConcentrationReachedCB

        ' Configure threshold for CO2 concentration "greater than 750 ppm"
        co2.SetCO2ConcentrationCallbackThreshold(">"C, 750, 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 BrickletCO2(ByVal uid As String, ByVal ipcon As IPConnection)

Creates an object with the unique device ID uid:

Dim co2 As New BrickletCO2("YOUR_DEVICE_UID", ipcon)

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

Function BrickletCO2.GetCO2Concentration() As Integer

Returns the measured CO2 concentration. The value is in ppm (parts per million) and between 0 to 10000.

If you want to get the CO2 concentration periodically, it is recommended to use the CO2ConcentrationCallback callback and set the period with SetCO2ConcentrationCallbackPeriod().

Advanced Functions

Function BrickletCO2.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 BrickletCO2.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 BrickletCO2.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:

  • BrickletCO2.FUNCTION_SET_CO2_CONCENTRATION_CALLBACK_PERIOD = 2
  • BrickletCO2.FUNCTION_SET_CO2_CONCENTRATION_CALLBACK_THRESHOLD = 4
  • BrickletCO2.FUNCTION_SET_DEBOUNCE_PERIOD = 6
Sub BrickletCO2.SetResponseExpectedAll(ByVal responseExpected As Boolean)

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

Sub BrickletCO2.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 BrickletCO2.SetCO2ConcentrationCallbackPeriod(ByVal period As Long)

Sets the period in ms with which the CO2ConcentrationCallback callback is triggered periodically. A value of 0 turns the callback off.

The CO2ConcentrationCallback callback is only triggered if the CO2 concentration has changed since the last triggering.

The default value is 0.

Function BrickletCO2.GetCO2ConcentrationCallbackPeriod() As Long

Returns the period as set by SetCO2ConcentrationCallbackPeriod().

Sub BrickletCO2.SetCO2ConcentrationCallbackThreshold(ByVal option As Char, ByVal min As Integer, ByVal max As Integer)

Sets the thresholds for the CO2ConcentrationReachedCallback callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the CO2 concentration is outside the min and max values
'i' Callback is triggered when the CO2 concentration is inside the min and max values
'<' Callback is triggered when the CO2 concentration is smaller than the min value (max is ignored)
'>' Callback is triggered when the CO2 concentration is greater than the min value (max is ignored)

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

The following constants are available for this function:

  • BrickletCO2.THRESHOLD_OPTION_OFF = "x"C
  • BrickletCO2.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletCO2.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletCO2.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletCO2.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletCO2.GetCO2ConcentrationCallbackThreshold(ByRef option As Char, ByRef min As Integer, ByRef max As Integer)

Returns the threshold as set by SetCO2ConcentrationCallbackThreshold().

The following constants are available for this function:

  • BrickletCO2.THRESHOLD_OPTION_OFF = "x"C
  • BrickletCO2.THRESHOLD_OPTION_OUTSIDE = "o"C
  • BrickletCO2.THRESHOLD_OPTION_INSIDE = "i"C
  • BrickletCO2.THRESHOLD_OPTION_SMALLER = "<"C
  • BrickletCO2.THRESHOLD_OPTION_GREATER = ">"C
Sub BrickletCO2.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 BrickletCO2.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 BrickletCO2, ByVal value As Short)
    Console.WriteLine("Value: {0}", value)
End Sub

AddHandler co2.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 BrickletCO2.CO2ConcentrationCallback(ByVal sender As BrickletCO2, ByVal co2Concentration As Integer)

This callback is triggered periodically with the period that is set by SetCO2ConcentrationCallbackPeriod(). The parameter is the CO2 concentration of the sensor.

The CO2ConcentrationCallback callback is only triggered if the CO2 concentration has changed since the last triggering.

Event BrickletCO2.CO2ConcentrationReachedCallback(ByVal sender As BrickletCO2, ByVal co2Concentration As Integer)

This callback is triggered when the threshold as set by SetCO2ConcentrationCallbackThreshold() is reached. The parameter is the CO2 concentration.

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

Constants

Const BrickletCO2.DEVICE_IDENTIFIER

This constant is used to identify a CO2 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 BrickletCO2.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a CO2 Bricklet.