MATLAB/Octave - Piezo Speaker Bricklet 2.0

This is the description of the MATLAB/Octave API bindings for the Piezo Speaker Bricklet 2.0. General information and technical specifications for the Piezo Speaker Bricklet 2.0 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).

Alarm (MATLAB)

Download (matlab_example_alarm.m)

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function matlab_example_alarm()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletPiezoSpeakerV2;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'XYZ'; % Change XYZ to the UID of your Piezo Speaker Bricklet 2.0

    ipcon = IPConnection(); % Create IP connection
    ps = handle(BrickletPiezoSpeakerV2(UID, ipcon), 'CallbackProperties'); % Create device object

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

    % 10 seconds of loud annoying fast alarm
    ps.setAlarm(800, 2000, 10, 1, 10, 10000);

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

Beep (MATLAB)

Download (matlab_example_beep.m)

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function matlab_example_beep()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletPiezoSpeakerV2;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'XYZ'; % Change XYZ to the UID of your Piezo Speaker Bricklet 2.0

    ipcon = IPConnection(); % Create IP connection
    ps = handle(BrickletPiezoSpeakerV2(UID, ipcon), 'CallbackProperties'); % Create device object

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

    % Make 2 second beep with a frequency of 1kHz
    ps.setBeep(1000, 0, 2000);

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

Alarm (Octave)

Download (octave_example_alarm.m)

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function octave_example_alarm()
    more off;

    HOST = "localhost";
    PORT = 4223;
    UID = "XYZ"; % Change XYZ to the UID of your Piezo Speaker Bricklet 2.0

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection
    ps = javaObject("com.tinkerforge.BrickletPiezoSpeakerV2", UID, ipcon); % Create device object

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

    % 10 seconds of loud annoying fast alarm
    ps.setAlarm(800, 2000, 10, 1, 10, 10000);

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

Beep (Octave)

Download (octave_example_beep.m)

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function octave_example_beep()
    more off;

    HOST = "localhost";
    PORT = 4223;
    UID = "XYZ"; % Change XYZ to the UID of your Piezo Speaker Bricklet 2.0

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection
    ps = javaObject("com.tinkerforge.BrickletPiezoSpeakerV2", UID, ipcon); % Create device object

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

    % Make 2 second beep with a frequency of 1kHz
    ps.setBeep(1000, 0, 2000);

    input("Press key to exit\n", "s");
    ipcon.disconnect();
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 BrickletPiezoSpeakerV2(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid.

In MATLAB:

import com.tinkerforge.BrickletPiezoSpeakerV2;

piezoSpeakerV2 = BrickletPiezoSpeakerV2('YOUR_DEVICE_UID', ipcon);

In Octave:

piezoSpeakerV2 = java_new("com.tinkerforge.BrickletPiezoSpeakerV2", "YOUR_DEVICE_UID", ipcon);

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

public void setBeep(int frequency, int volume, long duration)

Beeps with the given frequency and volume for the duration in ms.

For example: If you set a duration of 1000, with a volume of 10 and a frequency value of 2000 the piezo buzzer will beep with maximum loudness for one second with a frequency of 2 kHz.

A duration of 0 stops the current beep if any is ongoing. A duration of 4294967295 results in an infinite beep.

The ranges are:

  • Frequency: 50Hz - 15000Hz
  • Volume: 0 - 10
  • Duration: 0ms - 4294967295ms

The following constants are available for this function:

  • BrickletPiezoSpeakerV2.BEEP_DURATION_OFF = 0
  • BrickletPiezoSpeakerV2.BEEP_DURATION_INFINITE = 4294967295
public BrickletPiezoSpeakerV2.Beep getBeep()

Returns the last beep settings as set by setBeep(). If a beep is currently running it also returns the remaining duration of the beep in ms.

If the frequency or volume is updated during a beep (with updateFrequency() or updateVolume()) this function returns the updated value.

The following constants are available for this function:

  • BrickletPiezoSpeakerV2.BEEP_DURATION_OFF = 0
  • BrickletPiezoSpeakerV2.BEEP_DURATION_INFINITE = 4294967295

The returned object has the public member variables int frequency, int volume, long duration and long durationRemaining.

public void setAlarm(int startFrequency, int endFrequency, int stepSize, int stepDelay, int volume, long duration)

Creates an alarm (a tone that goes back and force between two specified frequencies).

The following parameters can be set:

  • Start Frequency: Start frequency of the alarm in Hz.
  • End Frequency: End frequency of the alarm in Hz.
  • Step Size: Size of one step of the sweep between the start/end frequencies in Hz.
  • Step Delay: Delay between two steps (duration of time that one tone is used in a sweep) in ms.
  • Duration: Duration of the alarm in ms.

A duration of 0 stops the current alarm if any is ongoing. A duration of 4294967295 results in an infinite alarm.

Below you can find two sets of example settings that you can try out. You can use these as a starting point to find an alarm signal that suits your application.

Example 1: 10 seconds of loud annoying fast alarm

  • Start Frequency = 800
  • End Frequency = 2000
  • Step Size = 10
  • Step Delay = 1
  • Volume = 10
  • Duration = 10000

Example 2: 10 seconds of soft siren sound with slow build-up

  • Start Frequency = 250
  • End Frequency = 750
  • Step Size = 1
  • Step Delay = 5
  • Volume = 0
  • Duration = 10000

The ranges are:

  • Start Frequency: 50Hz - 14999Hz (has to be smaller than end frequency)
  • End Frequency: 51Hz - 15000Hz (has to be bigger than start frequency)
  • Step Size: 1Hz - 65535Hz (has to be small enough to fit into the frequency range)
  • Step Delay: 1ms - 65535ms (has to be small enough to fit into the duration)
  • Volume: 0 - 10
  • Duration: 0ms - 4294967295ms

The following constants are available for this function:

  • BrickletPiezoSpeakerV2.ALARM_DURATION_OFF = 0
  • BrickletPiezoSpeakerV2.ALARM_DURATION_INFINITE = 4294967295
public BrickletPiezoSpeakerV2.Alarm getAlarm()

Returns the last alarm settings as set by setAlarm(). If an alarm is currently running it also returns the remaining duration of the alarm in ms as well as the current frequency of the alarm in Hz.

If the volume is updated during a beep (with updateVolume()) this function returns the updated value.

The following constants are available for this function:

  • BrickletPiezoSpeakerV2.ALARM_DURATION_OFF = 0
  • BrickletPiezoSpeakerV2.ALARM_DURATION_INFINITE = 4294967295

The returned object has the public member variables int startFrequency, int endFrequency, int stepSize, int stepDelay, int volume, long duration, long durationRemaining and int currentFrequency.

public void updateVolume(int volume)

Updates the volume of an ongoing beep or alarm. The range of the volume is 0 to 10.

public void updateFrequency(int frequency)

Updates the frequency of an ongoing beep. The range of the frequency is 50Hz to 15000Hz.

Advanced Functions

public int[] 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(int 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(int 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:

  • BrickletPiezoSpeakerV2.FUNCTION_SET_BEEP = 1
  • BrickletPiezoSpeakerV2.FUNCTION_SET_ALARM = 3
  • BrickletPiezoSpeakerV2.FUNCTION_UPDATE_VOLUME = 5
  • BrickletPiezoSpeakerV2.FUNCTION_UPDATE_FREQUENCY = 6
  • BrickletPiezoSpeakerV2.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletPiezoSpeakerV2.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletPiezoSpeakerV2.FUNCTION_RESET = 243
  • BrickletPiezoSpeakerV2.FUNCTION_WRITE_UID = 248
public void setResponseExpectedAll(boolean responseExpected)

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

public BrickletPiezoSpeakerV2.SPITFPErrorCount getSPITFPErrorCount()

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

The returned object has the public member variables long errorCountAckChecksum, long errorCountMessageChecksum, long errorCountFrame and long errorCountOverflow.

public int setBootloaderMode(int mode)

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletPiezoSpeakerV2.BOOTLOADER_STATUS_OK = 0
  • BrickletPiezoSpeakerV2.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletPiezoSpeakerV2.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletPiezoSpeakerV2.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletPiezoSpeakerV2.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletPiezoSpeakerV2.BOOTLOADER_STATUS_CRC_MISMATCH = 5
public int getBootloaderMode()

Returns the current bootloader mode, see setBootloaderMode().

The following constants are available for this function:

  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletPiezoSpeakerV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
public void setWriteFirmwarePointer(long pointer)

Sets the firmware pointer for writeFirmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

public int writeFirmware(int[] data)

Writes 64 Bytes of firmware at the position as written by setWriteFirmwarePointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

public void setStatusLEDConfig(int config)

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

  • BrickletPiezoSpeakerV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletPiezoSpeakerV2.STATUS_LED_CONFIG_ON = 1
  • BrickletPiezoSpeakerV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletPiezoSpeakerV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getStatusLEDConfig()

Returns the configuration as set by setStatusLEDConfig()

The following constants are available for this function:

  • BrickletPiezoSpeakerV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletPiezoSpeakerV2.STATUS_LED_CONFIG_ON = 1
  • BrickletPiezoSpeakerV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletPiezoSpeakerV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getChipTemperature()

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

public void reset()

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

public void writeUID(long uid)

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

public long readUID()

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

public BrickletPiezoSpeakerV2.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, int[] hardwareVersion, int[] firmwareVersion and int deviceIdentifier.

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 BrickletPiezoSpeakerV2.BeepFinishedCallback

This callback is triggered if a beep set by setBeep() is finished

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 addBeepFinishedCallback() function. An added callback function can be removed with the removeBeepFinishedCallback() function.

public callback BrickletPiezoSpeakerV2.AlarmFinishedCallback

This callback is triggered if a alarm set by setAlarm() is finished

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 addAlarmFinishedCallback() function. An added callback function can be removed with the removeAlarmFinishedCallback() function.

Constants

public static final int BrickletPiezoSpeakerV2.DEVICE_IDENTIFIER

This constant is used to identify a Piezo Speaker Bricklet 2.0.

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.

public static final String BrickletPiezoSpeakerV2.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Piezo Speaker Bricklet 2.0.