MATLAB/Octave - Voltage Bricklet

This is the description of the MATLAB/Octave API bindings for the Voltage Bricklet. General information and technical specifications for the Voltage 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.BrickletVoltage;

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

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

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

    % Get current voltage
    voltage = v.getVoltage();
    fprintf('Voltage: %g V\n', voltage/1000.0);

    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.BrickletVoltage;

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

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

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

    % Register voltage callback to function cb_voltage
    set(v, 'VoltageCallback', @(h, e) cb_voltage(e));

    % Set period for voltage callback to 1s (1000ms)
    % Note: The voltage callback is only called every second
    %       if the voltage has changed since the last call!
    v.setVoltageCallbackPeriod(1000);

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

% Callback function for voltage callback
function cb_voltage(e)
    fprintf('Voltage: %g V\n', e.voltage/1000.0);
end

Threshold (MATLAB)

Download (matlab_example_threshold.m)

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function matlab_example_threshold()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletVoltage;

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

    ipcon = IPConnection(); % Create IP connection
    v = handle(BrickletVoltage(UID, ipcon), 'CallbackProperties'); % 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)
    v.setDebouncePeriod(10000);

    % Register voltage reached callback to function cb_voltage_reached
    set(v, 'VoltageReachedCallback', @(h, e) cb_voltage_reached(e));

    % Configure threshold for voltage "greater than 5 V"
    v.setVoltageCallbackThreshold('>', 5*1000, 0);

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

% Callback function for voltage reached callback
function cb_voltage_reached(e)
    fprintf('Voltage: %g V\n', e.voltage/1000.0);
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 Voltage Bricklet

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

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

    % Get current voltage
    voltage = v.getVoltage();
    fprintf("Voltage: %g V\n", voltage/1000.0);

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

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

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

    % Register voltage callback to function cb_voltage
    v.addVoltageCallback(@cb_voltage);

    % Set period for voltage callback to 1s (1000ms)
    % Note: The voltage callback is only called every second
    %       if the voltage has changed since the last call!
    v.setVoltageCallbackPeriod(1000);

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

% Callback function for voltage callback
function cb_voltage(e)
    fprintf("Voltage: %g V\n", e.voltage/1000.0);
end

Threshold (Octave)

Download (octave_example_threshold.m)

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function octave_example_threshold()
    more off;

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

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection
    v = javaObject("com.tinkerforge.BrickletVoltage", 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)
    v.setDebouncePeriod(10000);

    % Register voltage reached callback to function cb_voltage_reached
    v.addVoltageReachedCallback(@cb_voltage_reached);

    % Configure threshold for voltage "greater than 5 V"
    v.setVoltageCallbackThreshold(">", 5*1000, 0);

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

% Callback function for voltage reached callback
function cb_voltage_reached(e)
    fprintf("Voltage: %g V\n", e.voltage/1000.0);
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

class BrickletVoltage(String uid, IPConnection ipcon)
Parameters:
  • uid – Type: String
  • ipcon – Type: IPConnection
Returns:
  • voltage – Type: BrickletVoltage

Creates an object with the unique device ID uid.

In MATLAB:

import com.tinkerforge.BrickletVoltage;

voltage = BrickletVoltage('YOUR_DEVICE_UID', ipcon);

In Octave:

voltage = java_new("com.tinkerforge.BrickletVoltage", "YOUR_DEVICE_UID", ipcon);

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

int BrickletVoltage.getVoltage()
Returns:
  • voltage – Type: int, Range: [0 to 216 - 1]

Returns the voltage of the sensor. The value is in mV and between 0mV and 50000mV.

If you want to get the voltage periodically, it is recommended to use the VoltageCallback callback and set the period with setVoltageCallbackPeriod().

Advanced Functions

int BrickletVoltage.getAnalogValue()
Returns:
  • value – Type: int, Range: [0 to 216 - 1]

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 getVoltage() 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 AnalogValueCallback callback and set the period with setAnalogValueCallbackPeriod().

short[] BrickletVoltage.getAPIVersion()
Returns:
  • apiVersion – Type: short[], Length: 3, Range: [0 to 255]

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.

boolean BrickletVoltage.getResponseExpected(short functionId)
Parameters:
  • functionId – Type: short, 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 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:

For functionId:

  • BrickletVoltage.FUNCTION_SET_VOLTAGE_CALLBACK_PERIOD = 3
  • BrickletVoltage.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BrickletVoltage.FUNCTION_SET_VOLTAGE_CALLBACK_THRESHOLD = 7
  • BrickletVoltage.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BrickletVoltage.FUNCTION_SET_DEBOUNCE_PERIOD = 11
void BrickletVoltage.setResponseExpected(short functionId, boolean responseExpected)
Parameters:
  • functionId – Type: short, 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 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:

For functionId:

  • BrickletVoltage.FUNCTION_SET_VOLTAGE_CALLBACK_PERIOD = 3
  • BrickletVoltage.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BrickletVoltage.FUNCTION_SET_VOLTAGE_CALLBACK_THRESHOLD = 7
  • BrickletVoltage.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BrickletVoltage.FUNCTION_SET_DEBOUNCE_PERIOD = 11
void BrickletVoltage.setResponseExpectedAll(boolean responseExpected)
Parameters:
  • responseExpected – Type: boolean

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

BrickletVoltage.Identity BrickletVoltage.getIdentity()
Return Object:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: char
  • hardwareVersion – Type: short[], Length: 3, Range: [0 to 255]
  • firmwareVersion – Type: short[], Length: 3, 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' 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 BrickletVoltage.setVoltageCallbackPeriod(long period)
Parameters:
  • period – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

The VoltageCallback callback is only triggered if the voltage has changed since the last triggering.

long BrickletVoltage.getVoltageCallbackPeriod()
Returns:
  • period – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by setVoltageCallbackPeriod().

void BrickletVoltage.setAnalogValueCallbackPeriod(long period)
Parameters:
  • period – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

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

The AnalogValueCallback callback is only triggered if the analog value has changed since the last triggering.

long BrickletVoltage.getAnalogValueCallbackPeriod()
Returns:
  • period – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by setAnalogValueCallbackPeriod().

void BrickletVoltage.setVoltageCallbackThreshold(char option, int min, int max)
Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: int, Range: [0 to 216 - 1]
  • max – Type: int, Range: [0 to 216 - 1]

Sets the thresholds for the VoltageReachedCallback callback.

The following options are possible:

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

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

The following constants are available for this function:

For option:

  • BrickletVoltage.THRESHOLD_OPTION_OFF = 'x'
  • BrickletVoltage.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletVoltage.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletVoltage.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletVoltage.THRESHOLD_OPTION_GREATER = '>'
BrickletVoltage.VoltageCallbackThreshold BrickletVoltage.getVoltageCallbackThreshold()
Return Object:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: int, Range: [0 to 216 - 1]
  • max – Type: int, Range: [0 to 216 - 1]

Returns the threshold as set by setVoltageCallbackThreshold().

The following constants are available for this function:

For option:

  • BrickletVoltage.THRESHOLD_OPTION_OFF = 'x'
  • BrickletVoltage.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletVoltage.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletVoltage.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletVoltage.THRESHOLD_OPTION_GREATER = '>'
void BrickletVoltage.setAnalogValueCallbackThreshold(char option, int min, int max)
Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: int, Range: [0 to 216 - 1]
  • max – Type: int, Range: [0 to 216 - 1]

Sets the thresholds for the AnalogValueReachedCallback 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:

For option:

  • BrickletVoltage.THRESHOLD_OPTION_OFF = 'x'
  • BrickletVoltage.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletVoltage.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletVoltage.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletVoltage.THRESHOLD_OPTION_GREATER = '>'
BrickletVoltage.AnalogValueCallbackThreshold BrickletVoltage.getAnalogValueCallbackThreshold()
Return Object:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: int, Range: [0 to 216 - 1]
  • max – Type: int, Range: [0 to 216 - 1]

Returns the threshold as set by setAnalogValueCallbackThreshold().

The following constants are available for this function:

For option:

  • BrickletVoltage.THRESHOLD_OPTION_OFF = 'x'
  • BrickletVoltage.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletVoltage.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletVoltage.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletVoltage.THRESHOLD_OPTION_GREATER = '>'
void BrickletVoltage.setDebouncePeriod(long debounce)
Parameters:
  • debounce – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Sets the period with which the threshold callbacks

are triggered, if the thresholds

keep being reached.

long BrickletVoltage.getDebouncePeriod()
Returns:
  • debounce – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

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 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.

callback BrickletVoltage.VoltageCallback
Event Object:
  • voltage – Type: int, Range: [0 to 216 - 1]

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

The VoltageCallback callback is only triggered if the voltage has changed since the last triggering.

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 addVoltageCallback() function. An added callback function can be removed with the removeVoltageCallback() function.

callback BrickletVoltage.AnalogValueCallback
Event Object:
  • value – Type: int, Range: [0 to 216 - 1]

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

The AnalogValueCallback callback is only triggered if the voltage has changed since the last triggering.

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 addAnalogValueCallback() function. An added callback function can be removed with the removeAnalogValueCallback() function.

callback BrickletVoltage.VoltageReachedCallback
Event Object:
  • voltage – Type: int, Range: [0 to 216 - 1]

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

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

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 addVoltageReachedCallback() function. An added callback function can be removed with the removeVoltageReachedCallback() function.

callback BrickletVoltage.AnalogValueReachedCallback
Event Object:
  • value – Type: int, Range: [0 to 216 - 1]

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().

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 addAnalogValueReachedCallback() function. An added callback function can be removed with the removeAnalogValueReachedCallback() function.

Constants

int BrickletVoltage.DEVICE_IDENTIFIER

This constant is used to identify a Voltage 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 BrickletVoltage.DEVICE_DISPLAY_NAME

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