Software / API Bindings / Java / API Reference and Examples / Bricklets / Joystick Bricklet

Java - Joystick Bricklet¶

This is the description of the Java API bindings for the Joystick Bricklet. General information and technical specifications for the Joystick Bricklet are summarized in its hardware description.

An installation guide for the Java API bindings is part of their general description.

Examples¶

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

Simple¶

Download (ExampleSimple.java)

import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletJoystick;
import com.tinkerforge.BrickletJoystick.Position;

public class ExampleSimple {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your Joystick Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletJoystick j = new BrickletJoystick(UID, ipcon); // Create device object

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

        // Get current position
        Position position = j.getPosition(); // Can throw com.tinkerforge.TimeoutException

        System.out.println("Position [X]: " + position.x);
        System.out.println("Position [Y]: " + position.y);

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Callback¶

Download (ExampleCallback.java)

import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletJoystick;

public class ExampleCallback {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your Joystick Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletJoystick j = new BrickletJoystick(UID, ipcon); // Create device object

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

        // Add pressed listener
        j.addPressedListener(new BrickletJoystick.PressedListener() {
            public void pressed() {
                System.out.println("Pressed");
            }
        });

        // Add released listener
        j.addReleasedListener(new BrickletJoystick.ReleasedListener() {
            public void released() {
                System.out.println("Released");
            }
        });

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Find Borders¶

Download (ExampleFindBorders.java)

import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletJoystick;

public class ExampleFindBorders {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your Joystick Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletJoystick j = new BrickletJoystick(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 0.2 seconds (200ms)
        j.setDebouncePeriod(200);

        // Add position reached listener
        j.addPositionReachedListener(new BrickletJoystick.PositionReachedListener() {
            public void positionReached(short x, short y) {
                if(y == 100) {
                    System.out.println("Top");
                } else if(y == -100) {
                    System.out.println("Bottom");
                }

                if(x == 100) {
                    System.out.println("Right");
                } else if(x == -100) {
                    System.out.println("Left");
                }

                System.out.println("");
            }
        });

        // Configure threshold for position "outside of -99, -99 to 99, 99"
        j.setPositionCallbackThreshold('o', (short)(-99), (short)99, (short)(-99),
                                       (short)99);

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

API¶

Generally, every method of the Java bindings that returns a value can throw a 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 unplugs the device). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Beside the TimeoutException there is also a NotConnectedException that is thrown if a method needs to communicate with the device while the IP Connection is not connected.

Since Java does not support multiple return values and return by reference is not possible for primitive types, we use small classes that only consist of member variables. The member variables of the returned objects are described in the corresponding method descriptions.

The package for all Brick/Bricklet bindings and the IP Connection is com.tinkerforge.*

All methods listed below are thread-safe.

Basic Functions¶

class BrickletJoystick(String uid, IPConnection ipcon)¶

Parameters:	uid – Type: String ipcon – Type: IPConnection
Returns:	joystick – Type: BrickletJoystick

Creates an object with the unique device ID uid:

BrickletJoystick joystick = new BrickletJoystick("YOUR_DEVICE_UID", ipcon);

This object can then be used after the IP Connection is connected.

BrickletJoystick.Position BrickletJoystick.getPosition()¶

Return Object:	x – Type: short, Range: [-100 to 100] y – Type: short, Range: [-100 to 100]

Returns the position of the joystick. The middle position of the joystick is x=0, y=0. The returned values are averaged and calibrated (see calibrate()).

If you want to get the position periodically, it is recommended to use the PositionListener listener and set the period with setPositionCallbackPeriod().

boolean BrickletJoystick.isPressed()¶

Returns:	pressed – Type: boolean

Returns true if the button is pressed and false otherwise.

It is recommended to use the PressedListener and ReleasedListener listeners to handle the button.

Advanced Functions¶

BrickletJoystick.AnalogValue BrickletJoystick.getAnalogValue()¶

Return Object:	x – Type: int, Range: [0 to 2¹² - 1] y – Type: int, Range: [0 to 2¹² - 1]

Returns the values as read by a 12-bit analog-to-digital converter.

Note

The values returned by getPosition() are 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 values periodically, it is recommended to use the AnalogValueListener listener and set the period with setAnalogValueCallbackPeriod().

void BrickletJoystick.calibrate()¶

Calibrates the middle position of the joystick. If your Joystick Bricklet does not return x=0 and y=0 in the middle position, call this function while the joystick is standing still in the middle position.

The resulting calibration will be saved on the EEPROM of the Joystick Bricklet, thus you only have to calibrate it once.

BrickletJoystick.Identity BrickletJoystick.getIdentity()¶

Return Object:

Return Object:	uid – Type: String, Length: up to 8 connectedUid – Type: String, Length: up to 8 position – Type: char, Range: ['a' to 'h', 'z'] hardwareVersion – Type: short[], Length: 3 0: major – Type: short, Range: [0 to 255] 1: minor – Type: short, Range: [0 to 255] 2: revision – Type: short, Range: [0 to 255] firmwareVersion – Type: short[], Length: 3 0: major – Type: short, Range: [0 to 255] 1: minor – Type: short, Range: [0 to 255] 2: revision – Type: short, Range: [0 to 255] deviceIdentifier – Type: int, Range: [0 to 2¹⁶ - 1]

uid – Type: String, Length: up to 8
connectedUid – Type: String, Length: up to 8
position – Type: char, Range: ['a' to 'h', 'z']
hardwareVersion – Type: short[], Length: 3

0: major – Type: short, Range: [0 to 255]
1: minor – Type: short, Range: [0 to 255]
2: revision – Type: short, Range: [0 to 255]

firmwareVersion – Type: short[], Length: 3

0: major – Type: short, Range: [0 to 255]
1: minor – Type: short, Range: [0 to 255]
2: revision – Type: short, 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). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

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

Listener Configuration Functions¶

void BrickletJoystick.setPositionCallbackPeriod(long period)¶

Parameters:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Sets the period with which the PositionListener listener is triggered periodically. A value of 0 turns the listener off.

The PositionListener listener is only triggered if the position has changed since the last triggering.

long BrickletJoystick.getPositionCallbackPeriod()¶

Returns:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by setPositionCallbackPeriod().

void BrickletJoystick.setAnalogValueCallbackPeriod(long period)¶

Parameters:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Sets the period with which the AnalogValueListener listener is triggered periodically. A value of 0 turns the listener off.

The AnalogValueListener listener is only triggered if the analog values have changed since the last triggering.

long BrickletJoystick.getAnalogValueCallbackPeriod()¶

Returns:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by setAnalogValueCallbackPeriod().

void BrickletJoystick.setPositionCallbackThreshold(char option, short minX, short maxX, short minY, short maxY)¶

Parameters:	option – Type: char, Range: See constants, Default: 'x' minX – Type: short, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 maxX – Type: short, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 minY – Type: short, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 maxY – Type: short, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0

Sets the thresholds for the PositionReachedListener listener.

The following options are possible:

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

The following constants are available for this function:

For option:

BrickletJoystick.THRESHOLD_OPTION_OFF = 'x'
BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletJoystick.THRESHOLD_OPTION_INSIDE = 'i'
BrickletJoystick.THRESHOLD_OPTION_SMALLER = '<'
BrickletJoystick.THRESHOLD_OPTION_GREATER = '>'

BrickletJoystick.PositionCallbackThreshold BrickletJoystick.getPositionCallbackThreshold()¶

Return Object:	option – Type: char, Range: See constants, Default: 'x' minX – Type: short, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 maxX – Type: short, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 minY – Type: short, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0 maxY – Type: short, Range: [-2¹⁵ to 2¹⁵ - 1], Default: 0

Returns the threshold as set by setPositionCallbackThreshold().

The following constants are available for this function:

For option:

BrickletJoystick.THRESHOLD_OPTION_OFF = 'x'
BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletJoystick.THRESHOLD_OPTION_INSIDE = 'i'
BrickletJoystick.THRESHOLD_OPTION_SMALLER = '<'
BrickletJoystick.THRESHOLD_OPTION_GREATER = '>'

void BrickletJoystick.setAnalogValueCallbackThreshold(char option, int minX, int maxX, int minY, int maxY)¶

Parameters:	option – Type: char, Range: See constants, Default: 'x' minX – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 maxX – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 minY – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 maxY – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0

Sets the thresholds for the AnalogValueReachedListener listener.

The following options are possible:

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

The following constants are available for this function:

For option:

BrickletJoystick.THRESHOLD_OPTION_OFF = 'x'
BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletJoystick.THRESHOLD_OPTION_INSIDE = 'i'
BrickletJoystick.THRESHOLD_OPTION_SMALLER = '<'
BrickletJoystick.THRESHOLD_OPTION_GREATER = '>'

BrickletJoystick.AnalogValueCallbackThreshold BrickletJoystick.getAnalogValueCallbackThreshold()¶

Return Object:	option – Type: char, Range: See constants, Default: 'x' minX – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 maxX – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 minY – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0 maxY – Type: int, Range: [0 to 2¹⁶ - 1], Default: 0

Returns the threshold as set by setAnalogValueCallbackThreshold().

The following constants are available for this function:

For option:

BrickletJoystick.THRESHOLD_OPTION_OFF = 'x'
BrickletJoystick.THRESHOLD_OPTION_OUTSIDE = 'o'
BrickletJoystick.THRESHOLD_OPTION_INSIDE = 'i'
BrickletJoystick.THRESHOLD_OPTION_SMALLER = '<'
BrickletJoystick.THRESHOLD_OPTION_GREATER = '>'

void BrickletJoystick.setDebouncePeriod(long debounce)¶

Parameters:	debounce – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100

Sets the period with which the threshold listeners

PositionReachedListener,
AnalogValueReachedListener

are triggered, if the thresholds

setPositionCallbackThreshold(),
setAnalogValueCallbackThreshold()

keep being reached.

long BrickletJoystick.getDebouncePeriod()¶

Returns:	debounce – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 100

Returns the debounce period as set by setDebouncePeriod().

Listeners¶

Listeners can be registered to receive time critical or recurring data from the device. The registration is done with add*Listener() functions of the device object.

The parameter is a listener class object, for example:

device.addExampleListener(new BrickletJoystick.ExampleListener() {
    public void property(int value) {
        System.out.println("Value: " + value);
    }
});

The available listener classes with inherent methods to be overwritten are described below. It is possible to add several listeners and to remove them with the corresponding remove*Listener() function.

Note

Using listeners 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.

class BrickletJoystick.PositionListener()¶

This listener can be added with the addPositionListener() function. An added listener can be removed with the removePositionListener() function.

void position(short x, short y)

Parameters:	x – Type: short, Range: [-100 to 100] y – Type: short, Range: [-100 to 100]

This listener is triggered periodically with the period that is set by setPositionCallbackPeriod(). The parameter is the position of the joystick.

The PositionListener listener is only triggered if the position has changed since the last triggering.

class BrickletJoystick.AnalogValueListener()¶

This listener can be added with the addAnalogValueListener() function. An added listener can be removed with the removeAnalogValueListener() function.

void analogValue(int x, int y)

Parameters:	x – Type: int, Range: [0 to 2¹² - 1] y – Type: int, Range: [0 to 2¹² - 1]

This listener is triggered periodically with the period that is set by setAnalogValueCallbackPeriod(). The parameters are the analog values of the joystick.

The AnalogValueListener listener is only triggered if the values have changed since the last triggering.

class BrickletJoystick.PositionReachedListener()¶

This listener can be added with the addPositionReachedListener() function. An added listener can be removed with the removePositionReachedListener() function.

void positionReached(short x, short y)

Parameters:	x – Type: short, Range: [-100 to 100] y – Type: short, Range: [-100 to 100]

This listener is triggered when the threshold as set by setPositionCallbackThreshold() is reached. The parameters are the position of the joystick.

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

class BrickletJoystick.AnalogValueReachedListener()¶

This listener can be added with the addAnalogValueReachedListener() function. An added listener can be removed with the removeAnalogValueReachedListener() function.

void analogValueReached(int x, int y)

Parameters:	x – Type: int, Range: [0 to 2¹² - 1] y – Type: int, Range: [0 to 2¹² - 1]

This listener is triggered when the threshold as set by setAnalogValueCallbackThreshold() is reached. The parameters are the analog values of the joystick.

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

class BrickletJoystick.PressedListener()¶

This listener can be added with the addPressedListener() function. An added listener can be removed with the removePressedListener() function.

void pressed(): This listener is triggered when the button is pressed.

class BrickletJoystick.ReleasedListener()¶

This listener can be added with the addReleasedListener() function. An added listener can be removed with the removeReleasedListener() function.

void released(): This listener 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.

short[] BrickletJoystick.getAPIVersion()¶

Return Object:	apiVersion – Type: short[], Length: 3 0: major – Type: short, Range: [0 to 255] 1: minor – Type: short, Range: [0 to 255] 2: revision – Type: short, 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.

boolean BrickletJoystick.getResponseExpected(byte functionId)¶

Parameters:	functionId – Type: byte, Range: See constants
Returns:	responseExpected – Type: boolean

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 listener 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

BrickletJoystick.FUNCTION_CALIBRATE = 4
BrickletJoystick.FUNCTION_SET_POSITION_CALLBACK_PERIOD = 5
BrickletJoystick.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 7
BrickletJoystick.FUNCTION_SET_POSITION_CALLBACK_THRESHOLD = 9
BrickletJoystick.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 11
BrickletJoystick.FUNCTION_SET_DEBOUNCE_PERIOD = 13

void BrickletJoystick.setResponseExpected(byte functionId, boolean responseExpected)¶

Parameters:	functionId – Type: byte, Range: See constants responseExpected – Type: boolean

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 listener configuration functions (default value: true). For getter functions it is always enabled.

The following constants are available for this function:

For functionId:

BrickletJoystick.FUNCTION_CALIBRATE = 4
BrickletJoystick.FUNCTION_SET_POSITION_CALLBACK_PERIOD = 5
BrickletJoystick.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 7
BrickletJoystick.FUNCTION_SET_POSITION_CALLBACK_THRESHOLD = 9
BrickletJoystick.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 11
BrickletJoystick.FUNCTION_SET_DEBOUNCE_PERIOD = 13

void BrickletJoystick.setResponseExpectedAll(boolean responseExpected)¶

Parameters:	responseExpected – Type: boolean

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

Constants¶

int BrickletJoystick.DEVICE_IDENTIFIER¶

This constant is used to identify a Joystick Bricklet.

The getIdentity() function and the IPConnection.EnumerateListener listener of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

String BrickletJoystick.DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a Joystick Bricklet.