C# - Rotary Encoder Bricklet

This is the description of the C# API bindings for the Rotary Encoder Bricklet. General information and technical specifications for the Rotary Encoder 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 Tinkerforge;

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

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

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

        // Get current count of encoder without reset
        int count = encoder.GetCount(false);

        System.Console.WriteLine("Count: " + count);

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

Callback

Download (ExampleCallback.cs)

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using Tinkerforge;

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

    // Callback function for count callback 
    static void CountCB(BrickletRotaryEncoder sender, int count)
    {
        System.Console.WriteLine("Count: " + count);
    }

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

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

        // Set Period for count callback to 0.05s (50ms)
        // Note: The count callback is only called every 50ms if the
        //       count has changed since the last call!
        encoder.SetCountCallbackPeriod(50);

        // Register count callback to function CountCB
        encoder.Count += CountCB;

        System.Console.WriteLine("Press enter to exit");
        System.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 BrickletRotaryEncoder(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletRotaryEncoder rotaryEncoder = new BrickletRotaryEncoder("YOUR_DEVICE_UID", ipcon);

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

public int GetCount(bool reset)

Returns the current count of the encoder. If you set reset to true, the count is set back to 0 directly after the current count is read.

The encoder has 24 steps per rotation

Turning the encoder to the left decrements the counter, so a negative count is possible.

public bool IsPressed()

Returns true if the button is pressed and false otherwise.

It is recommended to use the Pressed and Released callbacks to handle the button.

Advanced Functions

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 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:

  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_PERIOD = 2
  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_THRESHOLD = 4
  • BrickletRotaryEncoder.FUNCTION_SET_DEBOUNCE_PERIOD = 6
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 SetCountCallbackPeriod(long period)

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

Count is only triggered if the count has changed since the last triggering.

The default value is 0.

public long GetCountCallbackPeriod()

Returns the period as set by SetCountCallbackPeriod().

public void SetCountCallbackThreshold(char option, int min, int max)

Sets the thresholds for the CountReached callback.

The following options are possible:

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

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

The following constants are available for this function:

  • BrickletRotaryEncoder.THRESHOLD_OPTION_OFF = 'x'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_GREATER = '>'
public void GetCountCallbackThreshold(out char option, out int min, out int max)

Returns the threshold as set by SetCountCallbackThreshold().

The following constants are available for this function:

  • BrickletRotaryEncoder.THRESHOLD_OPTION_OFF = 'x'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_GREATER = '>'
public void SetDebouncePeriod(long debounce)

Sets the period in ms with which the threshold callback

is triggered, if the thresholds

keeps being reached.

The default value is 100.

public long GetDebouncePeriod()

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 appending your callback handler to the corresponding event:

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

rotaryEncoder.ExampleCallback += Callback;

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 Count(BrickletRotaryEncoder sender, int count)

This callback is triggered periodically with the period that is set by SetCountCallbackPeriod(). The parameter is the count of the encoder.

Count is only triggered if the count has changed since the last triggering.

public event CountReached(BrickletRotaryEncoder sender, int count)

This callback is triggered when the threshold as set by SetCountCallbackThreshold() is reached. The parameter is the count of the encoder.

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

public event Pressed(BrickletRotaryEncoder sender)

This callback is triggered when the button is pressed.

public event Released(BrickletRotaryEncoder sender)

This callback is triggered when the button is released.

Constants

public int DEVICE_IDENTIFIER

This constant is used to identify a Rotary Encoder 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.

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