C# - Hall Effect Bricklet

This is the description of the C# 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 C# API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (ExampleSimple.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your Hall Effect Bricklet

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletHallEffect he = 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 without reset
        long count = he.GetEdgeCount(false);
        Console.WriteLine("Count: " + count);

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

Callback

Download (ExampleCallback.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your Hall Effect Bricklet

    // Callback function for edge count callback
    static void EdgeCountCB(BrickletHallEffect sender, long count, bool value)
    {
        Console.WriteLine("Count: " + count);
    }

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletHallEffect he = new BrickletHallEffect(UID, ipcon); // Create device object

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

        // Register edge count callback to function EdgeCountCB
        he.EdgeCountCallback += EdgeCountCB;

        // Set period for edge count callback to 0.05s (50ms)
        // Note: The edge count callback is only called every 0.05 seconds
        //       if the edge count has changed since the last call!
        he.SetEdgeCountCallbackPeriod(50);

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

API

Generally, every method of the C# bindings that returns a value can throw a Tinkerforge.TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody plugs the device out). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Since C# does not support multiple return values directly, we use the out keyword to return multiple values from a method.

The namespace for all Brick/Bricklet bindings and the IPConnection is Tinkerforge.*.

All methods listed below are thread-safe.

Basic Functions

public class BrickletHallEffect(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletHallEffect hallEffect = new BrickletHallEffect("YOUR_DEVICE_UID", ipcon);

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

public bool GetValue()

Returns true if a magnetic field of 35 Gauss (3.5mT) or greater is detected.

public long GetEdgeCount(bool resetCounter)

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.

Advanced Functions

public void SetEdgeCountConfig(byte edgeType, byte debounce)

The edge type parameter configures if rising edges, falling edges or both are counted. Possible edge types are:

  • 0 = rising (default)
  • 1 = falling
  • 2 = both

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:

  • BrickletHallEffect.EDGE_TYPE_RISING = 0
  • BrickletHallEffect.EDGE_TYPE_FALLING = 1
  • BrickletHallEffect.EDGE_TYPE_BOTH = 2
public void GetEdgeCountConfig(out byte edgeType, out byte debounce)

Returns the edge type and debounce time as set by SetEdgeCountConfig().

The following constants are available for this function:

  • BrickletHallEffect.EDGE_TYPE_RISING = 0
  • BrickletHallEffect.EDGE_TYPE_FALLING = 1
  • BrickletHallEffect.EDGE_TYPE_BOTH = 2
public byte[] GetAPIVersion()

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.

public bool GetResponseExpected(byte functionId)

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.

public void SetResponseExpected(byte functionId, bool responseExpected)

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:

  • BrickletHallEffect.FUNCTION_SET_EDGE_COUNT_CONFIG = 3
  • BrickletHallEffect.FUNCTION_SET_EDGE_INTERRUPT = 5
  • BrickletHallEffect.FUNCTION_SET_EDGE_COUNT_CALLBACK_PERIOD = 7
public void SetResponseExpectedAll(bool responseExpected)

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

public void GetIdentity(out string uid, out string connectedUid, out char position, out byte[] hardwareVersion, out byte[] firmwareVersion, out int deviceIdentifier)

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

public void SetEdgeInterrupt(long edges)

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.

public long GetEdgeInterrupt()

Returns the edges as set by SetEdgeInterrupt().

public void SetEdgeCountCallbackPeriod(long period)

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

The EdgeCountCallback callback is only triggered if the edge count has changed since the last triggering.

The default value is 0.

public long GetEdgeCountCallbackPeriod()

Returns the period as set by SetEdgeCountCallbackPeriod().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by appending your callback handler to the corresponding event:

void MyCallback(BrickletHallEffect sender, int value)
{
    System.Console.WriteLine("Value: " + value);
}

hallEffect.ExampleCallback += MyCallback;

The available events 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.

public event EdgeCountCallback(BrickletHallEffect sender, long count, bool value)

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()).

The EdgeCountCallback callback is only triggered if the count or value changed since the last triggering.

Constants

public int DEVICE_IDENTIFIER

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.

public string DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Hall Effect Bricklet.