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 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 Rotary Encoder Bricklet

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletRotaryEncoder re = 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 without reset
        int count = re.GetCount(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 Rotary Encoder Bricklet

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

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

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

        // Register count callback to function CountCB
        re.CountCallback += CountCB;

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

class BrickletRotaryEncoder(String uid, IPConnection ipcon)
Parameters:
  • uid – Type: String
  • ipcon – Type: IPConnection
Returns:
  • rotaryEncoder – Type: BrickletRotaryEncoder

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).

int BrickletRotaryEncoder.GetCount(bool reset)
Parameters:
  • reset – Type: bool
Returns:
  • count – Type: int, Range: [-231 to 231 - 1]

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.

bool BrickletRotaryEncoder.IsPressed()
Returns:
  • pressed – Type: bool

Returns true if the button is pressed and false otherwise.

It is recommended to use the PressedCallback and ReleasedCallback callbacks to handle the button.

Advanced Functions

void BrickletRotaryEncoder.GetIdentity(out string uid, out string connectedUid, out char position, out byte[] hardwareVersion, out byte[] firmwareVersion, out int deviceIdentifier)
Output Parameters:
  • uid – Type: string, Length: up to 8
  • connectedUid – Type: string, Length: up to 8
  • position – Type: char, Range: ['a' to 'h', 'i', 'z']
  • hardwareVersion – Type: byte[], Length: 3
    • 0: major – Type: byte, Range: [0 to 255]
    • 1: minor – Type: byte, Range: [0 to 255]
    • 2: revision – Type: byte, Range: [0 to 255]
  • firmwareVersion – Type: byte[], Length: 3
    • 0: major – Type: byte, Range: [0 to 255]
    • 1: minor – Type: byte, Range: [0 to 255]
    • 2: revision – Type: byte, Range: [0 to 255]
  • deviceIdentifier – Type: int, Range: [0 to 216 - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

void BrickletRotaryEncoder.SetCountCallbackPeriod(long period)
Parameters:
  • period – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

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

long BrickletRotaryEncoder.GetCountCallbackPeriod()
Returns:
  • period – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by SetCountCallbackPeriod().

void BrickletRotaryEncoder.SetCountCallbackThreshold(char option, int min, int max)
Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: int, Range: [-231 to 231 - 1], Default: 0
  • max – Type: int, Range: [-231 to 231 - 1], Default: 0

Sets the thresholds for the CountReachedCallback 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 following constants are available for this function:

For option:

  • BrickletRotaryEncoder.THRESHOLD_OPTION_OFF = 'x'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_GREATER = '>'
void BrickletRotaryEncoder.GetCountCallbackThreshold(out char option, out int min, out int max)
Output Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: int, Range: [-231 to 231 - 1], Default: 0
  • max – Type: int, Range: [-231 to 231 - 1], Default: 0

Returns the threshold as set by SetCountCallbackThreshold().

The following constants are available for this function:

For option:

  • BrickletRotaryEncoder.THRESHOLD_OPTION_OFF = 'x'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletRotaryEncoder.THRESHOLD_OPTION_GREATER = '>'
void BrickletRotaryEncoder.SetDebouncePeriod(long debounce)
Parameters:
  • debounce – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Sets the period with which the threshold callback

is triggered, if the thresholds

keeps being reached.

long BrickletRotaryEncoder.GetDebouncePeriod()
Returns:
  • debounce – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

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

rotaryEncoder.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.

event BrickletRotaryEncoder.CountCallback(BrickletRotaryEncoder sender, int count)
Callback Parameters:
  • sender – Type: BrickletRotaryEncoder
  • count – Type: int, Range: [-231 to 231 - 1]

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

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

event BrickletRotaryEncoder.CountReachedCallback(BrickletRotaryEncoder sender, int count)
Callback Parameters:
  • sender – Type: BrickletRotaryEncoder
  • count – Type: int, Range: [-231 to 231 - 1]

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().

event BrickletRotaryEncoder.PressedCallback(BrickletRotaryEncoder sender)
Callback Parameters:
  • sender – Type: BrickletRotaryEncoder

This callback is triggered when the button is pressed.

event BrickletRotaryEncoder.ReleasedCallback(BrickletRotaryEncoder sender)
Callback Parameters:
  • sender – Type: BrickletRotaryEncoder

This callback is triggered when the button is released.

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

byte[] BrickletRotaryEncoder.GetAPIVersion()
Output Parameters:
  • apiVersion – Type: byte[], Length: 3
    • 0: major – Type: byte, Range: [0 to 255]
    • 1: minor – Type: byte, Range: [0 to 255]
    • 2: revision – Type: byte, Range: [0 to 255]

Returns the version of the API definition 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.

bool BrickletRotaryEncoder.GetResponseExpected(byte functionId)
Parameters:
  • functionId – Type: byte, Range: See constants
Returns:
  • responseExpected – Type: bool

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.

The following constants are available for this function:

For functionId:

  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_PERIOD = 2
  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_THRESHOLD = 4
  • BrickletRotaryEncoder.FUNCTION_SET_DEBOUNCE_PERIOD = 6
void BrickletRotaryEncoder.SetResponseExpected(byte functionId, bool responseExpected)
Parameters:
  • functionId – Type: byte, Range: See constants
  • responseExpected – Type: bool

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 constants are available for this function:

For functionId:

  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_PERIOD = 2
  • BrickletRotaryEncoder.FUNCTION_SET_COUNT_CALLBACK_THRESHOLD = 4
  • BrickletRotaryEncoder.FUNCTION_SET_DEBOUNCE_PERIOD = 6
void BrickletRotaryEncoder.SetResponseExpectedAll(bool responseExpected)
Parameters:
  • responseExpected – Type: bool

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

Constants

int BrickletRotaryEncoder.DEVICE_IDENTIFIER

This constant is used to identify a Rotary Encoder Bricklet.

The GetIdentity() function and the IPConnection.EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

string BrickletRotaryEncoder.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Rotary Encoder Bricklet.