C# - Distance US Bricklet

This is the description of the C# API bindings for the Distance US Bricklet. General information and technical specifications for the Distance US 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 Distance US Bricklet

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

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

        // Get current distance value
        int distance = dus.GetDistanceValue();
        Console.WriteLine("Distance Value: " + distance);

        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 Distance US Bricklet

    // Callback function for distance value callback
    static void DistanceCB(BrickletDistanceUS sender, int distance)
    {
        Console.WriteLine("Distance Value: " + distance);
    }

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

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

        // Register distance value callback to function DistanceCB
        dus.DistanceCallback += DistanceCB;

        // Set period for distance value callback to 0.2s (200ms)
        // Note: The distance value callback is only called every 0.2 seconds
        //       if the distance value has changed since the last call!
        dus.SetDistanceCallbackPeriod(200);

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

Threshold

Download (ExampleThreshold.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 Distance US Bricklet

    // Callback function for distance value reached callback
    static void DistanceReachedCB(BrickletDistanceUS sender, int distance)
    {
        Console.WriteLine("Distance Value: " + distance);
    }

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletDistanceUS dus = new BrickletDistanceUS(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)
        dus.SetDebouncePeriod(10000);

        // Register distance value reached callback to function DistanceReachedCB
        dus.DistanceReachedCallback += DistanceReachedCB;

        // Configure threshold for distance value "smaller than 200"
        dus.SetDistanceCallbackThreshold('<', 200, 0);

        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 BrickletDistanceUS(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletDistanceUS distanceUS = new BrickletDistanceUS("YOUR_DEVICE_UID", ipcon);

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

int BrickletDistanceUS.GetDistanceValue()

Returns the current distance value measured by the sensor. The value has a range of 0 to 4095. A small value corresponds to a small distance, a big value corresponds to a big distance. The relation between the measured distance value and the actual distance is affected by the 5V supply voltage (deviations in the supply voltage result in deviations in the distance values) and is non-linear (resolution is bigger at close range).

If you want to get the distance value periodically, it is recommended to use the DistanceCallback callback and set the period with SetDistanceCallbackPeriod().

Advanced Functions

void BrickletDistanceUS.SetMovingAverage(byte average)

Sets the length of a moving averaging for the distance value.

Setting the length to 0 will turn the averaging completely off. With less averaging, there is more noise on the data.

The range for the averaging is 0-100.

The default value is 20.

byte BrickletDistanceUS.GetMovingAverage()

Returns the length moving average as set by SetMovingAverage().

byte[] BrickletDistanceUS.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.

bool BrickletDistanceUS.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.

The following constants are available for this function:

  • BrickletDistanceUS.FUNCTION_SET_DISTANCE_CALLBACK_PERIOD = 2
  • BrickletDistanceUS.FUNCTION_SET_DISTANCE_CALLBACK_THRESHOLD = 4
  • BrickletDistanceUS.FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletDistanceUS.FUNCTION_SET_MOVING_AVERAGE = 10
void BrickletDistanceUS.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 constants are available for this function:

  • BrickletDistanceUS.FUNCTION_SET_DISTANCE_CALLBACK_PERIOD = 2
  • BrickletDistanceUS.FUNCTION_SET_DISTANCE_CALLBACK_THRESHOLD = 4
  • BrickletDistanceUS.FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletDistanceUS.FUNCTION_SET_MOVING_AVERAGE = 10
void BrickletDistanceUS.SetResponseExpectedAll(bool responseExpected)

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

void BrickletDistanceUS.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

void BrickletDistanceUS.SetDistanceCallbackPeriod(long period)

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

Der DistanceCallback callback is only triggered if the distance value has changed since the last triggering.

The default value is 0.

long BrickletDistanceUS.GetDistanceCallbackPeriod()

Returns the period as set by SetDistanceCallbackPeriod().

void BrickletDistanceUS.SetDistanceCallbackThreshold(char option, int min, int max)

Sets the thresholds for the DistanceReachedCallback callback.

The following options are possible:

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

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

The following constants are available for this function:

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

Returns the threshold as set by SetDistanceCallbackThreshold().

The following constants are available for this function:

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

Sets the period in ms with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

The default value is 100.

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

distanceUS.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 BrickletDistanceUS.DistanceCallback(BrickletDistanceUS sender, int distance)

This callback is triggered periodically with the period that is set by SetDistanceCallbackPeriod(). The parameter is the distance value of the sensor.

The DistanceCallback callback is only triggered if the distance value has changed since the last triggering.

event BrickletDistanceUS.DistanceReachedCallback(BrickletDistanceUS sender, int distance)

This callback is triggered when the threshold as set by SetDistanceCallbackThreshold() is reached. The parameter is the distance value of the sensor.

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

Constants

int BrickletDistanceUS.DEVICE_IDENTIFIER

This constant is used to identify a Distance US 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 BrickletDistanceUS.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Distance US Bricklet.