Note
This Bricklet is currently in the prototype stage and the software/hardware as well as the documentation is in an incomplete state.
This is the description of the MATLAB/Octave API bindings for the Accelerometer Bricklet. General information and technical specifications for the Accelerometer Bricklet are summarized in its hardware description.
An installation guide for the MATLAB/Octave API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
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 22 23 | function matlab_example_simple()
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletAccelerometer;
HOST = 'localhost';
PORT = 4223;
UID = 'sad'; % Change to your UID
ipcon = IPConnection(); % Create IP connection
acc = BrickletAccelerometer(UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% Don't use device before ipcon is connected
% Get current acceleration
acceleration = acc.getAcceleration();
fprintf('Acceleration(X): %gG\n', acceleration.x/1000.0);
fprintf('Acceleration(Y): %gG\n', acceleration.y/1000.0);
fprintf('Acceleration(Z): %gG\n', acceleration.z/1000.0);
input('Press any key to exit...\n', 's');
ipcon.disconnect();
end
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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 31 32 | function matlab_example_callback()
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletAccelerometer;
HOST = 'localhost';
PORT = 4223;
UID = 'sad'; % Change to your UID
ipcon = IPConnection(); % Create IP connection
acc = BrickletAccelerometer(UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% Don't use device before ipcon is connected
% Set Period for acceleration callback to 1s (1000ms)
% Note: The acceleration is only called every second if the
% acceleration has changed since the last call!
acc.setAccelerationCallbackPeriod(1000);
% Register acceleration callback to function cb_acceleration
set(acc, 'AccelerationCallback', @(h, e) cb_acceleration(e));
input('Press any key to exit...\n', 's');
ipcon.disconnect();
end
% Callback function for acceleration callback
function cb_acceleration(e)
fprintf('Acceleration(X): %gG\n', e.x/1000.0);
fprintf('Acceleration(Y): %gG\n', e.y/1000.0);
fprintf('Acceleration(Z): %gG\n', e.z/1000.0);
end
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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 33 | function matlab_example_threshold()
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletAccelerometer;
HOST = 'localhost';
PORT = 4223;
UID = 'sad'; % Change to your UID
ipcon = IPConnection(); % Create IP connection
acc = BrickletAccelerometer(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)
acc.setDebouncePeriod(10000);
% Register threshold reached callback to function cb_reached
set(acc, 'AccelerationReachedCallback', @(h, e) cb_reached(e));
% Configure threshold for acceleration values X, Y or Z greater than 2G
acc.setAccelerationCallbackThreshold('>', 2000, 0, 2000, 0, 2000, 0);
input('Press any key to exit...\n', 's');
ipcon.disconnect();
end
% Callback for acceleration greater than 2G
function cb_reached(e)
fprintf('Acceleration(X): %gG\n', e.x/1000.0);
fprintf('Acceleration(Y): %gG\n', e.y/1000.0);
fprintf('Acceleration(Z): %gG\n', e.z/1000.0);
end
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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 21 22 | function octave_example_simple()
more off;
HOST = "localhost";
PORT = 4223;
UID = "sad"; % Change to your UID
ipcon = java_new("com.tinkerforge.IPConnection"); % Create IP connection
acc = java_new("com.tinkerforge.BrickletAccelerometer", UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% Don't use device before ipcon is connected
% Get current acceleration
acceleration = acc.getAcceleration();
fprintf("Acceleration(X): %gG\n", acceleration.x / 1000.0);
fprintf("Acceleration(Y): %gG\n", acceleration.y / 1000.0);
fprintf("Acceleration(Z): %gG\n", acceleration.z / 1000.0);
input("Press any key to exit...\n", "s");
ipcon.disconnect();
end
|
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 30 31 | function octave_example_callback()
more off;
HOST = "localhost";
PORT = 4223;
UID = "abc"; % Change to your UID
ipcon = java_new("com.tinkerforge.IPConnection"); % Create IP connection
acc = java_new("com.tinkerforge.BrickletAccelerometer", UID, ipcon); % Create device object
ipcon.connect(HOST, PORT); % Connect to brickd
% Don't use device before ipcon is connected
% Set Period for acceleration callback to 1s (1000ms)
% Note: The acceleration callback is only called every second if the
% acceleration has changed since the last call!
acc.setAccelerationCallbackPeriod(1000);
% Register acceleration callback to function cb_acceleration
acc.addAccelerationCallback(@cb_acceleration);
input("Press any key to exit...\n", "s");
ipcon.disconnect();
end
% Callback function for acceleration callback
function cb_acceleration(e)
fprintf("Acceleration(X): %gG\n", e.r/1000.0);
fprintf("Acceleration(Y): %gG\n", e.g/1000.0);
fprintf("Acceleration(Z): %gG\n", e.b/1000.0);
end
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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 32 | function octave_example_threshold()
more off;
HOST = "localhost";
PORT = 4223;
UID = "sad"; % Change to your UID
ipcon = java_new("com.tinkerforge.IPConnection"); % Create IP connection
acc = java_new("com.tinkerforge.BrickletAccelerometer", 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)
acc.setDebouncePeriod(10000);
% Configure threshold for acceleration values X, Y or Z greater than 2G
acc.setAccelerationCallbackThreshold(acc.THRESHOLD_OPTION_GREATER, 2000, 0, 2000, 0, 2000, 0);
% Register threshold reached callback to function cb_reached
acc.addAccelerationReachedCallback(@cb_reached);
input("Press any key to exit...\n", "s");
ipcon.disconnect();
end
% Callback function for acceleration callback
function cb_reached(e)
fprintf("Acceleration(X): %gG\n", e.x/1000.0);
fprintf("Acceleration(Y): %gG\n", e.y/1000.0);
fprintf("Acceleration(Z): %gG\n", e.z/1000.0);
end
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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.
Creates an object with the unique device ID uid.
In MATLAB:
import com.tinkerforge.BrickletAccelerometer;
accelerometer = BrickletAccelerometer('YOUR_DEVICE_UID', ipcon);
In Octave:
accelerometer = java_new("com.tinkerforge.BrickletAccelerometer", "YOUR_DEVICE_UID", ipcon);
This object can then be used after the IP Connection is connected (see examples above).
Returns the acceleration in x, y and z direction. The values are given in mG (1/1000 G).
If you want to get the acceleration periodically, it is recommended to use the callback AccelerationCallback and set the period with setAccelerationCallbackPeriod().
The returned object has the public member variables short x, short y and short z.
Returns the temperature of the accelerometer in °C.
Enables the LED on the Bricklet.
Disables the LED on the Bricklet.
Returns true if the LED is enabled, false otherwise.
Configures the data rate, full scale range and filter bandwidth. Possible values are:
Decreasing data rate or full scale range will also decrease the noise on the data.
The default values are 100Hz data rate, -4G to +4G range and 200Hz filter bandwidth.
The following constants are available for this function:
Returns the configuration as set by setConfiguration().
The following constants are available for this function:
The returned object has the public member variables short dataRate, short fullScale and short filterBandwidth.
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.
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.
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:
Changes the response expected flag for all setter and callback configuration functions of this device at once.
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.
Sets the period in ms with which the AccelerationCallback callback is triggered periodically. A value of 0 turns the callback off.
AccelerationCallback is only triggered if the acceleration has changed since the last triggering.
The default value is 0.
Returns the period as set by setAccelerationCallbackPeriod().
Sets the thresholds for the AccelerationReachedCallback callback.
The following options are possible:
Option | Description |
---|---|
'x' | Callback is turned off |
'o' | Callback is triggered when the temperature is outside the min and max values |
'i' | Callback is triggered when the temperature is inside the min and max values |
'<' | Callback is triggered when the temperature is smaller than the min value (max is ignored) |
'>' | Callback is triggered when the temperature is greater than the min value (max is ignored) |
The default value is ('x', 0, 0, 0, 0, 0, 0).
The following constants are available for this function:
Returns the threshold as set by setAccelerationCallbackThreshold().
The following constants are available for this function:
The returned object has the public member variables char option, short minX, short maxX, short minY, short maxY, short minZ and short maxZ.
Sets the period in ms with which the threshold callback
is triggered, if the threshold
keeps being reached.
The default value is 100.
Returns the debounce period as set by setDebouncePeriod().
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.
Parameters: |
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This callback is triggered periodically with the period that is set by setAccelerationCallbackPeriod(). The parameters are the X, Y and Z acceleration.
AccelerationCallback is only triggered if the acceleration 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 addAccelerationCallback() function. An added callback function can be removed with the removeAccelerationCallback() function.
Parameters: |
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This callback is triggered when the threshold as set by setAccelerationCallbackThreshold() is reached. The parameters are the X, Y and Z acceleration.
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 addAccelerationReachedCallback() function. An added callback function can be removed with the removeAccelerationReachedCallback() function.
This constant is used to identify a Accelerometer 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.