C# - Distance IR Bricklet

This is the description of the C# API bindings for the Distance IR Bricklet. General information and technical specifications for the Distance IR 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 = "ABC"; // Change to your UID

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

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

        // Get current distance (unit is mm)
        int distance = dir.GetDistance();

        System.Console.WriteLine("Distance: " + distance/10.0 + " cm");

        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 = "ABC"; // Change to your UID

    // Callback function for distance callback (parameter has unit mm)
    static void DistanceCB(BrickletDistanceIR sender, int distance)
    {
        System.Console.WriteLine("Distance: " + distance/10.0 + " cm");
    }

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

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

        // Set Period for distance callback to 1s (1000ms)
        // Note: The distance callback is only called every second if the 
        //       distance has changed since the last call!
        dir.SetDistanceCallbackPeriod(1000);

        // Register distance callback to function DistanceCB
        dir.Distance += DistanceCB;

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

Threshold

Download (ExampleThreshold.cs)

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using Tinkerforge;

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

    // Callback for distance smaller than 20 cm
    static void ReachedCB(BrickletDistanceIR sender, int distance)
    {
        System.Console.WriteLine("Distance is smaller than 20 cm: " + distance/10.0 + " cm");
    }

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

        // Register threshold reached callback to function ReachedCB
        dir.DistanceReached += ReachedCB;

        // Configure threshold for "smaller than 20 cm" (unit is mm)
        dir.SetDistanceCallbackThreshold('<', 200, 0);

        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 BrickletDistanceIR(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletDistanceIR distanceIR = new BrickletDistanceIR("YOUR_DEVICE_UID", ipcon);

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

public int GetDistance()

Returns the distance measured by the sensor. The value is in mm and possible distance ranges are 40 to 300, 100 to 800 and 200 to 1500, depending on the selected IR sensor.

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

Advanced Functions

public int GetAnalogValue()

Returns the value as read by a 12-bit analog-to-digital converter. The value is between 0 and 4095.

Note

The value returned by GetDistance() is averaged over several samples to yield less noise, while GetAnalogValue() gives back raw unfiltered analog values. The only reason to use GetAnalogValue() is, if you need the full resolution of the analog-to-digital converter.

If you want the analog value periodically, it is recommended to use the callback AnalogValue and set the period with SetAnalogValueCallbackPeriod().

public void SetSamplingPoint(byte position, int distance)

Sets a sampling point value to a specific position of the lookup table. The lookup table comprises 128 equidistant analog values with corresponding distances.

If you measure a distance of 50cm at the analog value 2048, you should call this function with (64, 5000). The utilized analog-to-digital converter has a resolution of 12 bit. With 128 sampling points on the whole range, this means that every sampling point has a size of 32 analog values. Thus the analog value 2048 has the corresponding sampling point 64 = 2048/32.

Sampling points are saved on the EEPROM of the Distance IR Bricklet and loaded again on startup.

Note

An easy way to calibrate the sampling points of the Distance IR Bricklet is implemented in the Brick Viewer. If you want to calibrate your Bricklet it is highly recommended to use this implementation.

public int GetSamplingPoint(byte position)

Returns the distance to a sampling point position as set by SetSamplingPoint().

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:

  • BrickletDistanceIR.FUNCTION_SET_SAMPLING_POINT = 3
  • BrickletDistanceIR.FUNCTION_SET_DISTANCE_CALLBACK_PERIOD = 5
  • BrickletDistanceIR.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 7
  • BrickletDistanceIR.FUNCTION_SET_DISTANCE_CALLBACK_THRESHOLD = 9
  • BrickletDistanceIR.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 11
  • BrickletDistanceIR.FUNCTION_SET_DEBOUNCE_PERIOD = 13
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 SetDistanceCallbackPeriod(long period)

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

Distance is only triggered if the distance has changed since the last triggering.

The default value is 0.

public long GetDistanceCallbackPeriod()

Returns the period as set by SetDistanceCallbackPeriod().

public void SetAnalogValueCallbackPeriod(long period)

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

AnalogValue is only triggered if the analog value has changed since the last triggering.

The default value is 0.

public long GetAnalogValueCallbackPeriod()

Returns the period as set by SetAnalogValueCallbackPeriod().

public void SetDistanceCallbackThreshold(char option, short min, short max)

Sets the thresholds for the DistanceReached callback.

The following options are possible:

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

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

The following constants are available for this function:

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

Returns the threshold as set by SetDistanceCallbackThreshold().

The following constants are available for this function:

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

Sets the thresholds for the AnalogValueReached callback.

The following options are possible:

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

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

Returns the threshold as set by SetAnalogValueCallbackThreshold().

The following constants are available for this function:

  • BrickletDistanceIR.THRESHOLD_OPTION_OFF = 'x'
  • BrickletDistanceIR.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletDistanceIR.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletDistanceIR.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletDistanceIR.THRESHOLD_OPTION_GREATER = '>'
public void 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.

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

distanceIR.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 Distance(BrickletDistanceIR sender, int distance)

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

Distance is only triggered if the distance has changed since the last triggering.

public event AnalogValue(BrickletDistanceIR sender, int value)

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

AnalogValue is only triggered if the analog value has changed since the last triggering.

public event DistanceReached(BrickletDistanceIR sender, int distance)

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

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

public event AnalogValueReached(BrickletDistanceIR sender, int value)

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

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

Constants

public int DEVICE_IDENTIFIER

This constant is used to identify a Distance IR 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.

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