MATLAB/Octave - Humidity Bricklet

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

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
function matlab_example_simple()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletHumidity;

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

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

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

    % Get current humidity
    humidity = h.getHumidity();
    fprintf('Humidity: %g %%RH\n', humidity/10.0);

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

Callback (MATLAB)

Download (matlab_example_callback.m)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
function matlab_example_callback()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletHumidity;

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

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

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

    % Register humidity callback to function cb_humidity
    set(h, 'HumidityCallback', @(h, e) cb_humidity(e));

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

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

% Callback function for humidity callback
function cb_humidity(e)
    fprintf('Humidity: %g %%RH\n', e.humidity/10.0);
end

Threshold (MATLAB)

Download (matlab_example_threshold.m)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
function matlab_example_threshold()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletHumidity;

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

    ipcon = IPConnection(); % Create IP connection
    h = handle(BrickletHumidity(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)
    h.setDebouncePeriod(10000);

    % Register humidity reached callback to function cb_humidity_reached
    set(h, 'HumidityReachedCallback', @(h, e) cb_humidity_reached(e));

    % Configure threshold for humidity "outside of 30 to 60 %RH"
    h.setHumidityCallbackThreshold('o', 30*10, 60*10);

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

% Callback function for humidity reached callback
function cb_humidity_reached(e)
    fprintf('Humidity: %g %%RH\n', e.humidity/10.0);
    fprintf('Recommended humidity for human comfort is 30 to 60 %%RH.\n');
end

Simple (Octave)

Download (octave_example_simple.m)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
function octave_example_simple()
    more off;

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

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

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

    % Get current humidity
    humidity = h.getHumidity();
    fprintf("Humidity: %g %%RH\n", humidity/10.0);

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

Callback (Octave)

Download (octave_example_callback.m)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
function octave_example_callback()
    more off;

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

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

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

    % Register humidity callback to function cb_humidity
    h.addHumidityCallback(@cb_humidity);

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

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

% Callback function for humidity callback
function cb_humidity(e)
    fprintf("Humidity: %g %%RH\n", e.humidity/10.0);
end

Threshold (Octave)

Download (octave_example_threshold.m)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
function octave_example_threshold()
    more off;

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

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

    % Register humidity reached callback to function cb_humidity_reached
    h.addHumidityReachedCallback(@cb_humidity_reached);

    % Configure threshold for humidity "outside of 30 to 60 %RH"
    h.setHumidityCallbackThreshold("o", 30*10, 60*10);

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

% Callback function for humidity reached callback
function cb_humidity_reached(e)
    fprintf("Humidity: %g %%RH\n", e.humidity/10.0);
    fprintf("Recommended humidity for human comfort is 30 to 60 %%RH.\n");
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 BrickletHumidity(String uid, IPConnection ipcon)
Parameters:
  • uid – Type: String
  • ipcon – Type: IPConnection
Returns:
  • humidity – Type: BrickletHumidity

Creates an object with the unique device ID uid.

In MATLAB:

import com.tinkerforge.BrickletHumidity;

humidity = BrickletHumidity('YOUR_DEVICE_UID', ipcon);

In Octave:

humidity = java_new("com.tinkerforge.BrickletHumidity", "YOUR_DEVICE_UID", ipcon);

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

int BrickletHumidity.getHumidity()
Returns:
  • humidity – Type: int, Unit: 1/10 %, Range: [0 to 1000]

Returns the humidity of the sensor.

If you want to get the humidity periodically, it is recommended to use the HumidityCallback callback and set the period with setHumidityCallbackPeriod().

Advanced Functions

int BrickletHumidity.getAnalogValue()
Returns:
  • value – Type: int, Range: [0 to 212 - 1]

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

Note

The value returned by getHumidity() is averaged over several samples to yield less noise, while getAnalogValue() gives back raw unfiltered analog values. The returned humidity value is calibrated for room temperatures, if you use the sensor in extreme cold or extreme warm environments, you might want to calculate the humidity from the analog value yourself. See the HIH 5030 datasheet.

If you want the analog value periodically, it is recommended to use the AnalogValueCallback callback and set the period with setAnalogValueCallbackPeriod().

BrickletHumidity.Identity BrickletHumidity.getIdentity()
Return Object:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: char, Range: ['a' to 'h', 'i', 'z']
  • hardwareVersion – Type: short[], Length: 3
    • 1: major – Type: short, Range: [0 to 255]
    • 2: minor – Type: short, Range: [0 to 255]
    • 3: revision – Type: short, Range: [0 to 255]
  • firmwareVersion – Type: short[], Length: 3
    • 1: major – Type: short, Range: [0 to 255]
    • 2: minor – Type: short, Range: [0 to 255]
    • 3: 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). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

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

Callback Configuration Functions

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

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

The HumidityCallback callback is only triggered if the humidity has changed since the last triggering.

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

Returns the period as set by setHumidityCallbackPeriod().

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

Returns the period as set by setAnalogValueCallbackPeriod().

void BrickletHumidity.setHumidityCallbackThreshold(char option, int min, int max)
Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: int, Unit: 1/10 %, Range: [0 to 216 - 1], Default: 0
  • max – Type: int, Unit: 1/10 %, Range: [0 to 216 - 1], Default: 0

Sets the thresholds for the HumidityReachedCallback callback.

The following options are possible:

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

The following constants are available for this function:

For option:

  • BrickletHumidity.THRESHOLD_OPTION_OFF = 'x'
  • BrickletHumidity.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletHumidity.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletHumidity.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletHumidity.THRESHOLD_OPTION_GREATER = '>'
BrickletHumidity.HumidityCallbackThreshold BrickletHumidity.getHumidityCallbackThreshold()
Return Object:
  • option – Type: char, Range: See constants, Default: 'x'
  • min – Type: int, Unit: 1/10 %, Range: [0 to 216 - 1], Default: 0
  • max – Type: int, Unit: 1/10 %, Range: [0 to 216 - 1], Default: 0

Returns the threshold as set by setHumidityCallbackThreshold().

The following constants are available for this function:

For option:

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

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 following constants are available for this function:

For option:

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

  • BrickletHumidity.THRESHOLD_OPTION_OFF = 'x'
  • BrickletHumidity.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletHumidity.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletHumidity.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletHumidity.THRESHOLD_OPTION_GREATER = '>'
void BrickletHumidity.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 BrickletHumidity.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 BrickletHumidity.HumidityCallback
Event Object:
  • humidity – Type: int, Unit: 1/10 %, Range: [0 to 1000]

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

The HumidityCallback callback is only triggered if the humidity 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 addHumidityCallback() function. An added callback function can be removed with the removeHumidityCallback() function.

callback BrickletHumidity.AnalogValueCallback
Event Object:
  • value – Type: int, Range: [0 to 212 - 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 humidity 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 BrickletHumidity.HumidityReachedCallback
Event Object:
  • humidity – Type: int, Unit: 1/10 %, Range: [0 to 1000]

This callback is triggered when the threshold as set by setHumidityCallbackThreshold() is reached. The parameter is the humidity 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 addHumidityReachedCallback() function. An added callback function can be removed with the removeHumidityReachedCallback() function.

callback BrickletHumidity.AnalogValueReachedCallback
Event Object:
  • value – Type: int, Range: [0 to 212 - 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.

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[] BrickletHumidity.getAPIVersion()
Return Object:
  • apiVersion – Type: short[], Length: 3
    • 1: major – Type: short, Range: [0 to 255]
    • 2: minor – Type: short, Range: [0 to 255]
    • 3: 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 BrickletHumidity.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 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletHumidity.FUNCTION_SET_HUMIDITY_CALLBACK_PERIOD = 3
  • BrickletHumidity.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BrickletHumidity.FUNCTION_SET_HUMIDITY_CALLBACK_THRESHOLD = 7
  • BrickletHumidity.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BrickletHumidity.FUNCTION_SET_DEBOUNCE_PERIOD = 11
void BrickletHumidity.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 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletHumidity.FUNCTION_SET_HUMIDITY_CALLBACK_PERIOD = 3
  • BrickletHumidity.FUNCTION_SET_ANALOG_VALUE_CALLBACK_PERIOD = 5
  • BrickletHumidity.FUNCTION_SET_HUMIDITY_CALLBACK_THRESHOLD = 7
  • BrickletHumidity.FUNCTION_SET_ANALOG_VALUE_CALLBACK_THRESHOLD = 9
  • BrickletHumidity.FUNCTION_SET_DEBOUNCE_PERIOD = 11
void BrickletHumidity.setResponseExpectedAll(boolean responseExpected)
Parameters:
  • responseExpected – Type: boolean

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

Constants

int BrickletHumidity.DEVICE_IDENTIFIER

This constant is used to identify a Humidity 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 BrickletHumidity.DEVICE_DISPLAY_NAME

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