This is the description of the Visual Basic .NET API bindings for the Hall Effect Bricklet. General information and technical specifications for the Hall Effect 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 he As New BrickletHallEffect(UID, ipcon) ' Create device object
ipcon.Connect(HOST, PORT) ' Connect to brickd
' Don't use device before ipcon is connected
' Get current edge_count of Hall Effect Bricklet without reset
Dim edge_count As Long = he.GetEdgeCount(false)
System.Console.WriteLine("EdgeCount: " + edge_count.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 edge_count callback
Sub EdgeCountCB(ByVal sender As BrickletHallEffect, ByVal edge_count As Long, ByVal value As Boolean)
System.Console.WriteLine("Edge Count: " + edge_count.ToString())
End Sub
Sub Main()
Dim ipcon As New IPConnection() ' Create IP connection
Dim he As New BrickletHallEffect(UID, ipcon) ' Create device object
ipcon.Connect(HOST, PORT) ' Connect to brickd
' Don't use device before ipcon is connected
' Set Period for edge_count callback to 0.05s (50ms)
' Note: The edge_count callback is only called every 50ms if the
' edge_count has changed since the last call!
he.SetEdgeCountCallbackPeriod(50)
' Register edge count callback to EdgeCountCB
AddHandler he.EdgeCount, AddressOf EdgeCountCB
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 hallEffect As New BrickletHallEffect("YOUR_DEVICE_UID", ipcon)
This object can then be used after the IP Connection is connected (see examples above).
Returns true if a magnetic field of 35 Gauss (3.5mT) or greater is detected.
Returns the current value of the edge counter. You can configure edge type (rising, falling, both) that is counted with SetEdgeCountConfig().
If you set the reset counter to true, the count is set back to 0 directly after it is read.
The edge type parameter configures if rising edges, falling edges or both are counted. Possible edge types are:
A magnetic field of 35 Gauss (3.5mT) or greater causes a falling edge and a magnetic field of 25 Gauss (2.5mT) or smaller causes a rising edge.
If a magnet comes near the Bricklet the signal goes low (falling edge), if a magnet is removed from the vicinity the signal goes high (rising edge).
The debounce time is given in ms.
Configuring an edge counter resets its value to 0.
If you don't know what any of this means, just leave it at default. The default configuration is very likely OK for you.
Default values: 0 (edge type) and 100ms (debounce time)
The following constants are available for this function:
Returns the edge type and debounce time as set by SetEdgeCountConfig().
The following constants are available for this function:
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 number of edges until an interrupt is invoked.
If edges is set to n, an interrupt is invoked for every n-th detected edge.
If edges is set to 0, the interrupt is disabled.
Default value is 0.
Returns the edges as set by SetEdgeInterrupt().
Sets the period in ms with which the EdgeCount callback is triggered periodically. A value of 0 turns the callback off.
EdgeCount is only triggered if the edge count has changed since the last triggering.
The default value is 0.
Returns the period as set by SetEdgeCountCallbackPeriod().
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 BrickletHallEffect, ByVal value As Short) Console.WriteLine("Value: {0}", value) End Sub AddHandler hallEffect.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 SetEdgeCountCallbackPeriod(). The parameters are the current count and the current value (see GetValue() and GetEdgeCount()).
EdgeCount is only triggered if the count or value changed since the last triggering.
This constant is used to identify a Hall Effect 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.