MATLAB/Octave - Tilt Bricklet

This is the description of the MATLAB/Octave API bindings for the Tilt Bricklet. General information and technical specifications for the Tilt Bricklet are summarized in its hardware description.

An installation guide for the MATLAB/Octave API bindings is part of their general description.

Examples

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

Simple (MATLAB)

Download (matlab_example_simple.m)

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function matlab_example_simple()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletTilt;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'XYZ'; % Change XYZ to the UID of your Tilt Bricklet

    ipcon = IPConnection(); % Create IP connection
    t = handle(BrickletTilt(UID, ipcon), 'CallbackProperties'); % Create device object

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

    % Get current tilt state
    state = t.getTiltState();

    if state == BrickletTilt.TILT_STATE_CLOSED
        fprintf('Tilt State: Closed\n');
    elseif state == BrickletTilt.TILT_STATE_OPEN
        fprintf('Tilt State: Open\n');
    elseif state == BrickletTilt.TILT_STATE_CLOSED_VIBRATING
        fprintf('Tilt State: Closed Vibrating\n');
    end

    input('Press key to exit\n', 's');
    ipcon.disconnect();
end

Callback (MATLAB)

Download (matlab_example_callback.m)

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function matlab_example_callback()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletTilt;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'XYZ'; % Change XYZ to the UID of your Tilt Bricklet

    ipcon = IPConnection(); % Create IP connection
    t = handle(BrickletTilt(UID, ipcon), 'CallbackProperties'); % Create device object

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

    % Enable tilt state callback
    t.enableTiltStateCallback();

    % Register tilt state callback to function cb_tilt_state
    set(t, 'TiltStateCallback', @(h, e) cb_tilt_state(e));

    input('Press key to exit\n', 's');
    ipcon.disconnect();
end

% Callback function for tilt state callback
function cb_tilt_state(e)
    if e.state == com.tinkerforge.BrickletTilt.TILT_STATE_CLOSED
        fprintf('Tilt State: Closed\n');
    elseif e.state == com.tinkerforge.BrickletTilt.TILT_STATE_OPEN
        fprintf('Tilt State: Open\n');
    elseif e.state == com.tinkerforge.BrickletTilt.TILT_STATE_CLOSED_VIBRATING
        fprintf('Tilt State: Closed Vibrating\n');
    end
end

Simple (Octave)

Download (octave_example_simple.m)

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function octave_example_simple()
    more off;

    HOST = "localhost";
    PORT = 4223;
    UID = "XYZ"; % Change XYZ to the UID of your Tilt Bricklet

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection
    t = javaObject("com.tinkerforge.BrickletTilt", UID, ipcon); % Create device object

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

    % Get current tilt state
    state = t.getTiltState();

    if java2int(state) == 0
        fprintf("Tilt State: Closed\n");
    elseif java2int(state) == 1
        fprintf("Tilt State: Open\n");
    elseif java2int(state) == 2
        fprintf("Tilt State: Closed Vibrating\n");
    end

    input("Press key to exit\n", "s");
    ipcon.disconnect();
end

function int = java2int(value)
    if compare_versions(version(), "3.8", "<=")
        int = value.intValue();
    else
        int = value;
    end
end

Callback (Octave)

Download (octave_example_callback.m)

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function octave_example_callback()
    more off;

    HOST = "localhost";
    PORT = 4223;
    UID = "XYZ"; % Change XYZ to the UID of your Tilt Bricklet

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection
    t = javaObject("com.tinkerforge.BrickletTilt", UID, ipcon); % Create device object

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

    % Enable tilt state callback
    t.enableTiltStateCallback();

    % Register tilt state callback to function cb_tilt_state
    t.addTiltStateCallback(@cb_tilt_state);

    input("Press key to exit\n", "s");
    ipcon.disconnect();
end

% Callback function for tilt state callback
function cb_tilt_state(e)
    if java2int(e.state) == 0
        fprintf("Tilt State: Closed\n");
    elseif java2int(e.state) == 1
        fprintf("Tilt State: Open\n");
    elseif java2int(e.state) == 2
        fprintf("Tilt State: Closed Vibrating\n");
    end
end

function int = java2int(value)
    if compare_versions(version(), "3.8", "<=")
        int = value.intValue();
    else
        int = value;
    end
end

API

Generally, every method of the MATLAB 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 the MATLAB bindings are based on Java and 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

public class BrickletTilt(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid.

In MATLAB:

import com.tinkerforge.BrickletTilt;

tilt = BrickletTilt('YOUR_DEVICE_UID', ipcon);

In Octave:

tilt = java_new("com.tinkerforge.BrickletTilt", "YOUR_DEVICE_UID", ipcon);

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

public short getTiltState()

Returns the current tilt state. The state can either be

  • 0 = Closed: The ball in the tilt switch closes the circuit.
  • 1 = Open: The ball in the tilt switch does not close the circuit.
  • 2 = Closed Vibrating: The tilt switch is in motion (rapid change between open and close).
Tilt states

The following constants are available for this function:

  • BrickletTilt.TILT_STATE_CLOSED = 0
  • BrickletTilt.TILT_STATE_OPEN = 1
  • BrickletTilt.TILT_STATE_CLOSED_VIBRATING = 2

Advanced Functions

public short[] 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 boolean getResponseExpected(short 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(short functionId, boolean 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 function ID constants are available for this function:

  • BrickletTilt.FUNCTION_ENABLE_TILT_STATE_CALLBACK = 2
  • BrickletTilt.FUNCTION_DISABLE_TILT_STATE_CALLBACK = 3
public void setResponseExpectedAll(boolean responseExpected)

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

public BrickletTilt.Identity getIdentity()

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.

The returned object has the public member variables String uid, String connectedUid, char position, short[] hardwareVersion, short[] firmwareVersion and int deviceIdentifier.

Callback Configuration Functions

public void enableTiltStateCallback()

Enables the TiltStateCallback callback.

public void disableTiltStateCallback()

Disables the TiltStateCallback callback.

public boolean isTiltStateCallbackEnabled()

Returns true if the TiltStateCallback callback is enabled.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with "set" function of MATLAB. The parameters consist of the IP Connection object, the callback name and the callback function. For example, it looks like this in MATLAB:

function my_callback(e)
    fprintf('Parameter: %s\n', e.param);
end

set(device, 'ExampleCallback', @(h, e) my_callback(e));

Due to a difference in the Octave Java support the "set" function cannot be used in Octave. The registration is done with "add*Callback" functions of the device object. It looks like this in Octave:

function my_callback(e)
    fprintf("Parameter: %s\n", e.param);
end

device.addExampleCallback(@my_callback);

It is possible to add several callbacks and to remove them with the corresponding "remove*Callback" function.

The parameters of the callback are passed to the callback function as fields of the structure e, which is derived from the java.util.EventObject class. The available callback names with corresponding structure fields 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 callback BrickletTilt.TiltStateCallback
Parameters:state -- short

This callback provides the current tilt state. It is called every time the state changes.

See getTiltState() for a description of the states.

The following constants are available for this function:

  • BrickletTilt.TILT_STATE_CLOSED = 0
  • BrickletTilt.TILT_STATE_OPEN = 1
  • BrickletTilt.TILT_STATE_CLOSED_VIBRATING = 2

In MATLAB the set() function can be used to register a callback function to this callback.

In Octave a callback function can be added to this callback using the addTiltStateCallback() function. An added callback function can be removed with the removeTiltStateCallback() function.

Constants

public static final int BrickletTilt.DEVICE_IDENTIFIER

This constant is used to identify a Tilt 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.

public static final String BrickletTilt.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Tilt Bricklet.