MATLAB/Octave - Analog In Bricklet

This is the description of the MATLAB/Octave API bindings for the Analog In Bricklet. General information and technical specifications for the Analog In 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.BrickletAnalogIn;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'abd2'; % Change to your UID

    ipcon = IPConnection(); % Create IP connection
    ai = BrickletAnalogIn(UID, ipcon); % Create device object

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

    % Get current voltage (unit is mV)
    voltage = ai.getVoltage();
    fprintf('Voltage: %g V', voltage/1000.0);

    input('Press any 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.BrickletAnalogIn;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'abd2'; % Change to your UID

    ipcon = IPConnection(); % Create IP connection
    ai = BrickletAnalogIn(UID, ipcon); % Create device object

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

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

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

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

% Callback function for voltage callback (parameter has unit mV)
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.BrickletAnalogIn;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'abd2'; % Change to your UID

    ipcon = IPConnection(); % Create IP connection
    ai = BrickletAnalogIn(UID, ipcon); % Create device object

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

    % Set threshold callbacks with a debounce time of 10 seconds (10000ms)
    ai.setDebouncePeriod(10000);

    % Register threshold reached callback to function cb_reached
    set(ai, 'VoltageReachedCallback', @(h, e) cb_reached(e));

    % Configure threshold for "smaller than 5V" (unit is mV)
    ai.setVoltageCallbackThreshold('<', 5*1000, 0);

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

% Callback for voltage greater than 5V
function cb_reached(e)
    fprintf('Voltage dropped below 5V: %g\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 = "abd2"; % Change to your UID

    ipcon = java_new("com.tinkerforge.IPConnection"); % Create IP connection
    ai = java_new("com.tinkerforge.BrickletAnalogIn", UID, ipcon); % Create device object

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

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

    input("Press any 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 = "abd2"; % Change to your UID

    ipcon = java_new("com.tinkerforge.IPConnection"); % Create IP connection
    ai = java_new("com.tinkerforge.BrickletAnalogIn", UID, ipcon); % Create device object

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

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

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

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

% Callback function for voltage callback (parameter has unit mV)
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 = "abd2"; % Change to your UID

    ipcon = java_new("com.tinkerforge.IPConnection"); % Create IP connection
    ai = java_new("com.tinkerforge.BrickletAnalogIn", UID, ipcon); % Create device object

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

    % Set threshold callbacks with a debounce time of 10 seconds (10000ms)
    ai.setDebouncePeriod(10000);

    % Register threshold reached callback to function cb_reached
    ai.addVoltageReachedCallback(@cb_reached);

    % Configure threshold for "smaller than 5V" (unit is mV)
    ai.setVoltageCallbackThreshold(ai.THRESHOLD_OPTION_SMALLER, 5*1000, 0);
    
    input("Press any key to exit...\n", "s");
    ipcon.disconnect();
end

% Callback for voltage less than 5V
function cb_reached(e)
    fprintf("Voltage dropped below 5V: %g\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

public class BrickletAnalogIn(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid.

In MATLAB:

import com.tinkerforge.BrickletAnalogIn;

analogIn = BrickletAnalogIn('YOUR_DEVICE_UID', ipcon);

In Octave:

analogIn = java_new("com.tinkerforge.BrickletAnalogIn", "YOUR_DEVICE_UID", ipcon);

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

public int getVoltage()

Returns the voltage of the sensor. The value is in mV and between 0V and 45V. The resolution between 0 and 6V is about 2mV. Between 6 and 45V the resolution is about 10mV.

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

public void setRange(short range)

Sets the measurement range. Possible ranges:

  • 0: Automatically switched
  • 1: 0V - 6.05V,  1.48mV resolution
  • 2: 0V - 10.32V,  2.52mV resolution
  • 3: 0V - 36.30V,  8.86mV resolution
  • 4: 0V - 45.00V,  11.25mV resolution
  • 5: 0V - 3.3V,  0.81mV resolution, new in version 2.0.3 (Plugin)

The default measurement range is 0.

The following constants are available for this function:

  • BrickletAnalogIn.RANGE_AUTOMATIC = 0
  • BrickletAnalogIn.RANGE_UP_TO_6V = 1
  • BrickletAnalogIn.RANGE_UP_TO_10V = 2
  • BrickletAnalogIn.RANGE_UP_TO_36V = 3
  • BrickletAnalogIn.RANGE_UP_TO_45V = 4
  • BrickletAnalogIn.RANGE_UP_TO_3V = 5

New in version 2.0.1 (Plugin).

public short getRange()

Returns the measurement range as set by setRange().

The following constants are available for this function:

  • BrickletAnalogIn.RANGE_AUTOMATIC = 0
  • BrickletAnalogIn.RANGE_UP_TO_6V = 1
  • BrickletAnalogIn.RANGE_UP_TO_10V = 2
  • BrickletAnalogIn.RANGE_UP_TO_36V = 3
  • BrickletAnalogIn.RANGE_UP_TO_45V = 4
  • BrickletAnalogIn.RANGE_UP_TO_3V = 5

New in version 2.0.1 (Plugin).

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 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 callback AnalogValueCallback and set the period with setAnalogValueCallbackPeriod().

public void setAveraging(short average)

Set the length of a averaging for the voltage value.

Setting the length to 0 will turn the averaging completely off. If the averaging is off, there is more noise on the data, but the data is without delay.

The default value is 50.

New in version 2.0.3 (Plugin).

public short getAveraging()

Returns the averaging configuration as set by setAveraging().

New in version 2.0.3 (Plugin).

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 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:

  • BrickletAnalogIn.FUNCTION_SET_VOLTAGE_CALLBACK_PERIOD = 3
  • BrickletAnalogIn.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BrickletAnalogIn.FUNCTION_SET_VOLTAGE_CALLBACK_THRESHOLD = 7
  • BrickletAnalogIn.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BrickletAnalogIn.FUNCTION_SET_DEBOUNCE_PERIOD = 11
  • BrickletAnalogIn.FUNCTION_SET_RANGE = 17
  • BrickletAnalogIn.FUNCTION_SET_AVERAGING = 19
public void setResponseExpectedAll(boolean responseExpected)

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

public BrickletAnalogIn.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 setVoltageCallbackPeriod(long period)

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

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

The default value is 0.

public long getVoltageCallbackPeriod()

Returns the period as set by setVoltageCallbackPeriod().

public void setAnalogValueCallbackPeriod(long period)

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

AnalogValueCallback 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 setVoltageCallbackThreshold(char option, short min, short max)

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:

  • BrickletAnalogIn.THRESHOLD_OPTION_OFF = 'x'
  • BrickletAnalogIn.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletAnalogIn.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletAnalogIn.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletAnalogIn.THRESHOLD_OPTION_GREATER = '>'
public BrickletAnalogIn.VoltageCallbackThreshold getVoltageCallbackThreshold()

Returns the threshold as set by setVoltageCallbackThreshold().

The following constants are available for this function:

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

The returned object has the public member variables char option, short min and short max.

public void setAnalogValueCallbackThreshold(char option, int min, int max)

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:

  • BrickletAnalogIn.THRESHOLD_OPTION_OFF = 'x'
  • BrickletAnalogIn.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletAnalogIn.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletAnalogIn.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletAnalogIn.THRESHOLD_OPTION_GREATER = '>'
public BrickletAnalogIn.AnalogValueCallbackThreshold getAnalogValueCallbackThreshold()

Returns the threshold as set by setAnalogValueCallbackThreshold().

The following constants are available for this function:

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

The returned object has the public member variables char option, int min and int max.

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

set(device, 'ExampleCallback', @(h, e) cb_example(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 cb_example(e)
    fprintf("Parameter: %s\n", e.param);
end

device.addExampleCallback(@cb_example);

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 BrickletAnalogIn.VoltageCallback
Parameters:voltage -- int

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

VoltageCallback 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.

public callback BrickletAnalogIn.AnalogValueCallback
Parameters:value -- int

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

AnalogValueCallback 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.

public callback BrickletAnalogIn.VoltageReachedCallback
Parameters:voltage -- int

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.

public callback BrickletAnalogIn.AnalogValueReachedCallback
Parameters:value -- int

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

public static final int BrickletAnalogIn.DEVICE_IDENTIFIER

This constant is used to identify a Analog In 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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