Note
This Brick 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 IMU Brick 2.0. General information and technical specifications for the IMU Brick 2.0 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).
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.BrickIMUV2;
imuV2 = BrickIMUV2('YOUR_DEVICE_UID', ipcon);
In Octave:
imuV2 = java_new("com.tinkerforge.BrickIMUV2", "YOUR_DEVICE_UID", ipcon);
This object can then be used after the IP Connection is connected (see examples above).
Return all of the available data of the IMU Brick.
The calibration status consists of four pairs of two bits. Each pair of bits represents the status of the current calibration.
A value of 0 means for "not calibrated" and a value of 3 means "fully calibrated". In your program you should always be able to ignore the calibration status, it is used by the calibration window of the Brick Viewer and it can be ignored after the first calibration. See the documentation in the calibration window for more information regarding the calibration of the IMU Brick.
If you want to get the data periodically, it is recommended to use the callback AllDataCallback and set the period with setAllDataPeriod().
The returned object has the public member variables short[] acceleration, short[] magneticField, short[] angularVelocity, short[] eulerAngle, short[] quaternion, short[] linearAcceleration, short[] gravityVector, byte temperature and short calibrationStatus.
Turns the orientation and direction LEDs of the IMU Brick on.
Turns the orientation and direction LEDs of the IMU Brick off.
Returns true if the orientation and direction LEDs of the IMU Brick are on, false otherwise.
Returns the calibrated acceleration from the accelerometer for the x, y and z axis in 1/100 m/s².
If you want to get the acceleration periodically, it is recommended to use the callback AccelerationCallback and set the period with setAccelerationPeriod().
The returned object has the public member variables short x, short y and short z.
Returns the calibrated magnetic field from the magnetometer for the x, y and z axis in 1/16 µT (Microtesla).
If you want to get the magnetic field periodically, it is recommended to use the callback MagneticFieldCallback and set the period with setMagneticFieldPeriod().
The returned object has the public member variables short x, short y and short z.
Returns the calibrated angular velocity from the gyroscope for the x, y and z axis in 1/16 °/s.
If you want to get the angular velocity periodically, it is recommended to use the callback AngularVelocityCallback and set the period with setAngularVelocityPeriod().
The returned object has the public member variables short x, short y and short z.
Returns the temperature of the IMU Brick. The temperature is given in °C. The temperature is measured in the core of the BNO055 IC, it is not the ambient temperature
Returns the current orientation (heading, roll, pitch) of the IMU Brick as Euler angles in 1/16 degree. Note that Euler angles always experience a gimbal lock.
We recommend that you use quaternions instead.
The rotation angle has the following ranges:
If you want to get the orientation periodically, it is recommended to use the callback OrientationCallback and set the period with setOrientationPeriod().
The returned object has the public member variables short heading, short roll and short pitch.
Returns the linear acceleration of the IMU Brick for the x, y and z axis in 1/100 m/s².
The linear acceleration is the acceleration in each of the three axis of the IMU Brick with the influences of gravity removed.
It is also possible to get the gravity vector with the influence of linear acceleration removed, see getGravityVector().
If you want to get the linear acceleration periodically, it is recommended to use the callback LinearAccelerationCallback and set the period with setLinearAccelerationPeriod().
The returned object has the public member variables short x, short y and short z.
Returns the current gravity vector of the IMU Brick for the x, y and z axis in 1/100 m/s².
The gravity vector is the acceleration that occurs due to gravity. Influences of additional linear acceleration are removed.
It is also possible to get the linear acceleration with the influence of gravity removed, see getLinearAcceleration().
If you want to get the gravity vector periodically, it is recommended to use the callback GravityVectorCallback and set the period with setGravityVectorPeriod().
The returned object has the public member variables short x, short y and short z.
Returns the current orientation (w, x, y, z) of the IMU Brick as quaternions.
You have to divide the returns values by 16383 (14 bit) to get the usual range of -1.0 to +1.0 for quaternions.
If you want to get the quaternions periodically, it is recommended to use the callback QuaternionCallback and set the period with setQuaternionPeriod().
The returned object has the public member variables short w, short x, short y and short z.
A call of this function saves the current calibration to be used as a starting point for the next restart of continuous calibration of the IMU Brick.
A return value of true means that the calibration could be used and false means that it could not be used (this happens if the calibration status is not "fully calibrated").
This function is used by the calibration window of the Brick Viewer, you should not need to call it in your program.
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.
Enables the status LED.
The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.
The default state is enabled.
Disables the status LED.
The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.
The default state is enabled.
Returns true if the status LED is enabled, false otherwise.
Returns the firmware and protocol version and the name of the Bricklet for a given port.
This functions sole purpose is to allow automatic flashing of v1.x.y Bricklet plugins.
The returned object has the public member variables short protocolVersion, short[] firmwareVersion and String name.
Returns the temperature in °C/10 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 an accuracy of +-15%. Practically it is only useful as an indicator for temperature changes.
Calling this function will reset the Brick. Calling this function on a Brick inside of a stack will reset the whole stack.
After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!
Returns the UID, the UID where the Brick is connected to, the position, the hardware and firmware version as well as the device identifier.
The position can be '0'-'8' (stack position).
The device identifier numbers can be found here. There is also a constant for the device identifier of this Brick.
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.
The default value is 0.
Returns the period as set by setAccelerationPeriod().
Sets the period in ms with which the MagneticFieldCallback callback is triggered periodically. A value of 0 turns the callback off.
Returns the period as set by setMagneticFieldPeriod().
Sets the period in ms with which the AngularVelocityCallback callback is triggered periodically. A value of 0 turns the callback off.
Returns the period as set by setAngularVelocityPeriod().
Sets the period in ms with which the TemperatureCallback callback is triggered periodically. A value of 0 turns the callback off.
Returns the period as set by setTemperaturePeriod().
Sets the period in ms with which the OrientationCallback callback is triggered periodically. A value of 0 turns the callback off.
Returns the period as set by setOrientationPeriod().
Sets the period in ms with which the LinearAccelerationCallback callback is triggered periodically. A value of 0 turns the callback off.
Returns the period as set by setLinearAccelerationPeriod().
Sets the period in ms with which the GravityVectorCallback callback is triggered periodically. A value of 0 turns the callback off.
Returns the period as set by setGravityVectorPeriod().
Sets the period in ms with which the QuaternionCallback callback is triggered periodically. A value of 0 turns the callback off.
Returns the period as set by setQuaternionPeriod().
Sets the period in ms with which the AllDataCallback callback is triggered periodically. A value of 0 turns the callback off.
Returns the period as set by setAllDataPeriod().
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 setAccelerationPeriod(). The parameters are the acceleration for the x, y and z axis.
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 periodically with the period that is set by setMagneticFieldPeriod(). The parameters are the magnetic field for the x, y and z axis.
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 addMagneticFieldCallback() function. An added callback function can be removed with the removeMagneticFieldCallback() function.
Parameters: |
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This callback is triggered periodically with the period that is set by setAngularVelocityPeriod(). The parameters are the angular velocity for the x, y and z axis.
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 addAngularVelocityCallback() function. An added callback function can be removed with the removeAngularVelocityCallback() function.
Parameters: | temperature -- byte |
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This callback is triggered periodically with the period that is set by setTemperaturePeriod(). The parameter is the temperature.
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 addTemperatureCallback() function. An added callback function can be removed with the removeTemperatureCallback() function.
Parameters: |
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This callback is triggered periodically with the period that is set by setLinearAccelerationPeriod(). The parameters are the linear acceleration for the x, y and z axis.
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 addLinearAccelerationCallback() function. An added callback function can be removed with the removeLinearAccelerationCallback() function.
Parameters: |
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This callback is triggered periodically with the period that is set by setGravityVectorPeriod(). The parameters gravity vector for the x, y and z axis.
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 addGravityVectorCallback() function. An added callback function can be removed with the removeGravityVectorCallback() function.
Parameters: |
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This callback is triggered periodically with the period that is set by setOrientationPeriod(). The parameters are the orientation (heading (yaw), roll, pitch) of the IMU Brick in Euler angles. See getOrientation() for details.
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 addOrientationCallback() function. An added callback function can be removed with the removeOrientationCallback() function.
Parameters: |
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This callback is triggered periodically with the period that is set by setQuaternionPeriod(). The parameters are the orientation (x, y, z, w) of the IMU Brick in quaternions. See getQuaternion() for details.
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 addQuaternionCallback() function. An added callback function can be removed with the removeQuaternionCallback() function.
Parameters: |
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This callback is triggered periodically with the period that is set by setAllDataPeriod(). The parameters are as for getAllData().
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 addAllDataCallback() function. An added callback function can be removed with the removeAllDataCallback() function.
This constant is used to identify a IMU Brick 2.0.
The getIdentity() function and the EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.