Software / API Bindings / MATLAB/Octave / API Reference and Examples / Bricks (Discontinued) / IMU Brick

MATLAB/Octave - IMU Brick¶

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

function matlab_example_simple()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickIMU;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'XXYYZZ'; % Change XXYYZZ to the UID of your IMU Brick

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

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

    % Get current quaternion
    quaternion = imu.getQuaternion();

    fprintf('Quaternion [X]: %f\n', quaternion.x);
    fprintf('Quaternion [Y]: %f\n', quaternion.y);
    fprintf('Quaternion [Z]: %f\n', quaternion.z);
    fprintf('Quaternion [W]: %f\n', quaternion.w);

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

Callback (MATLAB)¶

Download (matlab_example_callback.m)

function matlab_example_callback()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickIMU;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'XXYYZZ'; % Change XXYYZZ to the UID of your IMU Brick

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

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

    % Register quaternion callback to function cb_quaternion
    set(imu, 'QuaternionCallback', @(h, e) cb_quaternion(e));

    % Set period for quaternion callback to 1s (1000ms)
    imu.setQuaternionPeriod(1000);

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

% Callback function for quaternion callback
function cb_quaternion(e)
    fprintf('Quaternion [X]: %f\n', e.x);
    fprintf('Quaternion [Y]: %f\n', e.y);
    fprintf('Quaternion [Z]: %f\n', e.z);
    fprintf('Quaternion [W]: %f\n', e.w);
    fprintf('\n');
end

Simple (Octave)¶

Download (octave_example_simple.m)

function octave_example_simple()
    more off;

    HOST = "localhost";
    PORT = 4223;
    UID = "XXYYZZ"; % Change XXYYZZ to the UID of your IMU Brick

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

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

    % Get current quaternion
    quaternion = imu.getQuaternion();

    fprintf("Quaternion [X]: %f\n", quaternion.x);
    fprintf("Quaternion [Y]: %f\n", quaternion.y);
    fprintf("Quaternion [Z]: %f\n", quaternion.z);
    fprintf("Quaternion [W]: %f\n", quaternion.w);

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

Callback (Octave)¶

Download (octave_example_callback.m)

function octave_example_callback()
    more off;

    HOST = "localhost";
    PORT = 4223;
    UID = "XXYYZZ"; % Change XXYYZZ to the UID of your IMU Brick

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

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

    % Register quaternion callback to function cb_quaternion
    imu.addQuaternionCallback(@cb_quaternion);

    % Set period for quaternion callback to 1s (1000ms)
    imu.setQuaternionPeriod(1000);

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

% Callback function for quaternion callback
function cb_quaternion(e)
    fprintf("Quaternion [X]: %f\n", e.x);
    fprintf("Quaternion [Y]: %f\n", e.y);
    fprintf("Quaternion [Z]: %f\n", e.z);
    fprintf("Quaternion [W]: %f\n", e.w);
    fprintf("\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 BrickIMU(String uid, IPConnection ipcon)¶

Parameters:	uid – Type: String ipcon – Type: IPConnection
Returns:	imu – Type: BrickIMU

Creates an object with the unique device ID uid.

In MATLAB:

import com.tinkerforge.BrickIMU;

imu = BrickIMU('YOUR_DEVICE_UID', ipcon);

In Octave:

imu = java_new("com.tinkerforge.BrickIMU", "YOUR_DEVICE_UID", ipcon);

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

BrickIMU.Orientation BrickIMU.getOrientation()¶

Return Object:	roll – Type: short, Unit: 1/100 °, Range: [-18000 to 18000] pitch – Type: short, Unit: 1/100 °, Range: [-18000 to 18000] yaw – Type: short, Unit: 1/100 °, Range: [-18000 to 18000]

Returns the current orientation (roll, pitch, yaw) of the IMU Brick as Euler angles. Note that Euler angles always experience a gimbal lock.

We recommend that you use quaternions instead.

The order to sequence in which the orientation values should be applied is roll, yaw, pitch.

If you want to get the orientation periodically, it is recommended to use the OrientationCallback callback and set the period with setOrientationPeriod().

BrickIMU.Quaternion BrickIMU.getQuaternion()¶

Return Object:	x – Type: float, Range: [-1.0 to 1.0] y – Type: float, Range: [-1.0 to 1.0] z – Type: float, Range: [-1.0 to 1.0] w – Type: float, Range: [-1.0 to 1.0]

Returns the current orientation (x, y, z, w) of the IMU as quaternions.

You can go from quaternions to Euler angles with the following formula:

xAngle = atan2(2*y*w - 2*x*z, 1 - 2*y*y - 2*z*z)
yAngle = atan2(2*x*w - 2*y*z, 1 - 2*x*x - 2*z*z)
zAngle =  asin(2*x*y + 2*z*w)

This process is not reversible, because of the gimbal lock.

It is also possible to calculate independent angles. You can calculate yaw, pitch and roll in a right-handed vehicle coordinate system according to DIN70000 with:

yaw   =  atan2(2*x*y + 2*w*z, w*w + x*x - y*y - z*z)
pitch = -asin(2*w*y - 2*x*z)
roll  = -atan2(2*y*z + 2*w*x, -w*w + x*x + y*y - z*z))

Converting the quaternions to an OpenGL transformation matrix is possible with the following formula:

matrix = [[1 - 2*(y*y + z*z),     2*(x*y - w*z),     2*(x*z + w*y), 0],
          [    2*(x*y + w*z), 1 - 2*(x*x + z*z),     2*(y*z - w*x), 0],
          [    2*(x*z - w*y),     2*(y*z + w*x), 1 - 2*(x*x + y*y), 0],
          [                0,                 0,                 0, 1]]

If you want to get the quaternions periodically, it is recommended to use the QuaternionCallback callback and set the period with setQuaternionPeriod().

void BrickIMU.ledsOn()¶: Turns the orientation and direction LEDs of the IMU Brick on.

void BrickIMU.ledsOff()¶: Turns the orientation and direction LEDs of the IMU Brick off.

boolean BrickIMU.areLedsOn()¶

Returns:	leds – Type: boolean, Default: true

Returns true if the orientation and direction LEDs of the IMU Brick are on, false otherwise.

void BrickIMU.setConvergenceSpeed(int speed)¶

Parameters:	speed – Type: int, Unit: 1 °/s, Range: [0 to 2¹⁶ - 1], Default: 30

Sets the convergence speed of the IMU Brick. The convergence speed determines how the different sensor measurements are fused.

If the orientation of the IMU Brick is off by 10° and the convergence speed is set to 20°/s, it will take 0.5s until the orientation is corrected. However, if the correct orientation is reached and the convergence speed is too high, the orientation will fluctuate with the fluctuations of the accelerometer and the magnetometer.

If you set the convergence speed to 0, practically only the gyroscope is used to calculate the orientation. This gives very smooth movements, but errors of the gyroscope will not be corrected. If you set the convergence speed to something above 500, practically only the magnetometer and the accelerometer are used to calculate the orientation. In this case the movements are abrupt and the values will fluctuate, but there won't be any errors that accumulate over time.

In an application with high angular velocities, we recommend a high convergence speed, so the errors of the gyroscope can be corrected fast. In applications with only slow movements we recommend a low convergence speed. You can change the convergence speed on the fly. So it is possible (and recommended) to increase the convergence speed before an abrupt movement and decrease it afterwards again.

You might want to play around with the convergence speed in the Brick Viewer to get a feeling for a good value for your application.

int BrickIMU.getConvergenceSpeed()¶

Returns:	speed – Type: int, Unit: 1 °/s, Range: [0 to 2¹⁶ - 1], Default: 30

Returns the convergence speed as set by setConvergenceSpeed().

Advanced Functions¶

BrickIMU.Acceleration BrickIMU.getAcceleration()¶

Return Object:	x – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] y – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] z – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the calibrated acceleration from the accelerometer for the x, y and z axis.

If you want to get the acceleration periodically, it is recommended to use the AccelerationCallback callback and set the period with setAccelerationPeriod().

BrickIMU.MagneticField BrickIMU.getMagneticField()¶

Return Object:	x – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] y – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] z – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the calibrated magnetic field from the magnetometer for the x, y and z axis.

If you want to get the magnetic field periodically, it is recommended to use the MagneticFieldCallback callback and set the period with setMagneticFieldPeriod().

BrickIMU.AngularVelocity BrickIMU.getAngularVelocity()¶

Return Object:	x – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] y – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] z – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750]

Returns the calibrated angular velocity from the gyroscope for the x, y and z axis in °/14.375s (you have to divide by 14.375 to get the value in °/s).

If you want to get the angular velocity periodically, it is recommended to use the AngularVelocityCallback callback and set the period with setAngularVelocityPeriod().

BrickIMU.AllData BrickIMU.getAllData()¶

Return Object:

Return Object:	accX – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] accY – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] accZ – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] magX – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] magY – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] magZ – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] angX – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] angY – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] angZ – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] temperature – Type: short, Unit: 1/100 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

accX – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
accY – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
accZ – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
magX – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
magY – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
magZ – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
angX – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750]
angY – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750]
angZ – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750]
temperature – Type: short, Unit: 1/100 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the data from getAcceleration(), getMagneticField() and getAngularVelocity() as well as the temperature of the IMU Brick.

If you want to get the data periodically, it is recommended to use the AllDataCallback callback and set the period with setAllDataPeriod().

short BrickIMU.getIMUTemperature()¶

Returns:	temperature – Type: short, Unit: 1/100 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the temperature of the IMU Brick.

void BrickIMU.setAccelerationRange(short range)¶

Parameters:	range – Type: short, Range: [0 to 255]

Not implemented yet.

short BrickIMU.getAccelerationRange()¶

Returns:	range – Type: short, Range: [0 to 255]

Not implemented yet.

void BrickIMU.setMagnetometerRange(short range)¶

Parameters:	range – Type: short, Range: [0 to 255]

Not implemented yet.

short BrickIMU.getMagnetometerRange()¶

Returns:	range – Type: short, Range: [0 to 255]

Not implemented yet.

void BrickIMU.setCalibration(short typ, short[] data)¶

Parameters:	typ – Type: short, Range: See constants data – Type: short[], Length: 10, Range: [-2¹⁵ to 2¹⁵ - 1]

There are several different types that can be calibrated:

Type	Description	Values
0	Accelerometer Gain	`[mul x, mul y, mul z, div x, div y, div z, 0, 0, 0, 0]`
1	Accelerometer Bias	`[bias x, bias y, bias z, 0, 0, 0, 0, 0, 0, 0]`
2	Magnetometer Gain	`[mul x, mul y, mul z, div x, div y, div z, 0, 0, 0, 0]`
3	Magnetometer Bias	`[bias x, bias y, bias z, 0, 0, 0, 0, 0, 0, 0]`
4	Gyroscope Gain	`[mul x, mul y, mul z, div x, div y, div z, 0, 0, 0, 0]`
5	Gyroscope Bias	`[bias xl, bias yl, bias zl, temp l, bias xh, bias yh, bias zh, temp h, 0, 0]`

The calibration via gain and bias is done with the following formula:

new_value = (bias + orig_value) * gain_mul / gain_div

If you really want to write your own calibration software, please keep in mind that you first have to undo the old calibration (set bias to 0 and gain to 1/1) and that you have to average over several thousand values to obtain a usable result in the end.

The gyroscope bias is highly dependent on the temperature, so you have to calibrate the bias two times with different temperatures. The values xl, yl, zl and temp l are the bias for x, y, z and the corresponding temperature for a low temperature. The values xh, yh, zh and temp h are the same for a high temperatures. The temperature difference should be at least 5°C. If you have a temperature where the IMU Brick is mostly used, you should use this temperature for one of the sampling points.

Note

We highly recommend that you use the Brick Viewer to calibrate your IMU Brick.

The following constants are available for this function:

For typ:

BrickIMU.CALIBRATION_TYPE_ACCELEROMETER_GAIN = 0
BrickIMU.CALIBRATION_TYPE_ACCELEROMETER_BIAS = 1
BrickIMU.CALIBRATION_TYPE_MAGNETOMETER_GAIN = 2
BrickIMU.CALIBRATION_TYPE_MAGNETOMETER_BIAS = 3
BrickIMU.CALIBRATION_TYPE_GYROSCOPE_GAIN = 4
BrickIMU.CALIBRATION_TYPE_GYROSCOPE_BIAS = 5

short[] BrickIMU.getCalibration(short typ)¶

Parameters:	typ – Type: short, Range: See constants
Returns:	data – Type: short[], Length: 10, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the calibration for a given type as set by setCalibration().

The following constants are available for this function:

For typ:

BrickIMU.CALIBRATION_TYPE_ACCELEROMETER_GAIN = 0
BrickIMU.CALIBRATION_TYPE_ACCELEROMETER_BIAS = 1
BrickIMU.CALIBRATION_TYPE_MAGNETOMETER_GAIN = 2
BrickIMU.CALIBRATION_TYPE_MAGNETOMETER_BIAS = 3
BrickIMU.CALIBRATION_TYPE_GYROSCOPE_GAIN = 4
BrickIMU.CALIBRATION_TYPE_GYROSCOPE_BIAS = 5

void BrickIMU.orientationCalculationOn()¶

Turns the orientation calculation of the IMU Brick on.

As default the calculation is on.

New in version 2.0.2 (Firmware).

void BrickIMU.orientationCalculationOff()¶

Turns the orientation calculation of the IMU Brick off.

If the calculation is off, getOrientation() will return the last calculated value until the calculation is turned on again.

The trigonometric functions that are needed to calculate the orientation are very expensive. We recommend to turn the orientation calculation off if the orientation is not needed, to free calculation time for the sensor fusion algorithm.

As default the calculation is on.

New in version 2.0.2 (Firmware).

boolean BrickIMU.isOrientationCalculationOn()¶

Returns:	orientationCalculationOn – Type: boolean, Default: true

Returns true if the orientation calculation of the IMU Brick is on, false otherwise.

New in version 2.0.2 (Firmware).

void BrickIMU.setSPITFPBaudrateConfig(boolean enableDynamicBaudrate, long minimumDynamicBaudrate)¶

Parameters:	enableDynamicBaudrate – Type: boolean, Default: true minimumDynamicBaudrate – Type: long, Unit: 1 Bd, Range: [400000 to 2000000], Default: 400000

The SPITF protocol can be used with a dynamic baudrate. If the dynamic baudrate is enabled, the Brick will try to adapt the baudrate for the communication between Bricks and Bricklets according to the amount of data that is transferred.

The baudrate will be increased exponentially if lots of data is sent/received and decreased linearly if little data is sent/received.

This lowers the baudrate in applications where little data is transferred (e.g. a weather station) and increases the robustness. If there is lots of data to transfer (e.g. Thermal Imaging Bricklet) it automatically increases the baudrate as needed.

In cases where some data has to transferred as fast as possible every few seconds (e.g. RS485 Bricklet with a high baudrate but small payload) you may want to turn the dynamic baudrate off to get the highest possible performance.

The maximum value of the baudrate can be set per port with the function setSPITFPBaudrate(). If the dynamic baudrate is disabled, the baudrate as set by setSPITFPBaudrate() will be used statically.

New in version 2.3.5 (Firmware).

BrickIMU.SPITFPBaudrateConfig BrickIMU.getSPITFPBaudrateConfig()¶

Return Object:	enableDynamicBaudrate – Type: boolean, Default: true minimumDynamicBaudrate – Type: long, Unit: 1 Bd, Range: [400000 to 2000000], Default: 400000

Returns the baudrate config, see setSPITFPBaudrateConfig().

New in version 2.3.5 (Firmware).

long BrickIMU.getSendTimeoutCount(short communicationMethod)¶

Parameters:	communicationMethod – Type: short, Range: See constants
Returns:	timeoutCount – Type: long, Range: [0 to 2³² - 1]

Returns the timeout count for the different communication methods.

The methods 0-2 are available for all Bricks, 3-7 only for Master Bricks.

This function is mostly used for debugging during development, in normal operation the counters should nearly always stay at 0.

The following constants are available for this function:

For communicationMethod:

BrickIMU.COMMUNICATION_METHOD_NONE = 0
BrickIMU.COMMUNICATION_METHOD_USB = 1
BrickIMU.COMMUNICATION_METHOD_SPI_STACK = 2
BrickIMU.COMMUNICATION_METHOD_CHIBI = 3
BrickIMU.COMMUNICATION_METHOD_RS485 = 4
BrickIMU.COMMUNICATION_METHOD_WIFI = 5
BrickIMU.COMMUNICATION_METHOD_ETHERNET = 6
BrickIMU.COMMUNICATION_METHOD_WIFI_V2 = 7

New in version 2.3.3 (Firmware).

void BrickIMU.setSPITFPBaudrate(char brickletPort, long baudrate)¶

Parameters:	brickletPort – Type: char, Range: ['a' to 'b'] baudrate – Type: long, Unit: 1 Bd, Range: [400000 to 2000000], Default: 1400000

Sets the baudrate for a specific Bricklet port.

If you want to increase the throughput of Bricklets you can increase the baudrate. If you get a high error count because of high interference (see getSPITFPErrorCount()) you can decrease the baudrate.

If the dynamic baudrate feature is enabled, the baudrate set by this function corresponds to the maximum baudrate (see setSPITFPBaudrateConfig()).

Regulatory testing is done with the default baudrate. If CE compatibility or similar is necessary in your applications we recommend to not change the baudrate.

New in version 2.3.3 (Firmware).

long BrickIMU.getSPITFPBaudrate(char brickletPort)¶

Parameters:	brickletPort – Type: char, Range: ['a' to 'b']
Returns:	baudrate – Type: long, Unit: 1 Bd, Range: [400000 to 2000000], Default: 1400000

Returns the baudrate for a given Bricklet port, see setSPITFPBaudrate().

New in version 2.3.3 (Firmware).

BrickIMU.SPITFPErrorCount BrickIMU.getSPITFPErrorCount(char brickletPort)¶

Parameters:	brickletPort – Type: char, Range: ['a' to 'b']
Return Object:	errorCountACKChecksum – Type: long, Range: [0 to 2³² - 1] errorCountMessageChecksum – Type: long, Range: [0 to 2³² - 1] errorCountFrame – Type: long, Range: [0 to 2³² - 1] errorCountOverflow – Type: long, Range: [0 to 2³² - 1]

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

ACK checksum errors,
message checksum errors,
framing errors and
overflow errors.

The errors counts are for errors that occur on the Brick side. All Bricklets have a similar function that returns the errors on the Bricklet side.

New in version 2.3.3 (Firmware).

void BrickIMU.enableStatusLED()¶

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.

New in version 2.3.1 (Firmware).

void BrickIMU.disableStatusLED()¶

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.

New in version 2.3.1 (Firmware).

boolean BrickIMU.isStatusLEDEnabled()¶

Returns:	enabled – Type: boolean, Default: true

Returns true if the status LED is enabled, false otherwise.

New in version 2.3.1 (Firmware).

short BrickIMU.getChipTemperature()¶

Returns:	temperature – Type: short, Unit: 1/10 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the temperature 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.

void BrickIMU.reset()¶

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!

BrickIMU.Identity BrickIMU.getIdentity()¶

Return Object:

Return Object:	uid – Type: String, Length: up to 8 connectedUid – Type: String, Length: up to 8 position – Type: char, Range: ['0' to '8'] 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]

uid – Type: String, Length: up to 8
connectedUid – Type: String, Length: up to 8
position – Type: char, Range: ['0' to '8']
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 Brick is connected to, the position, the hardware and firmware version as well as the device identifier.

The position is the position in the stack from '0' (bottom) to '8' (top).

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

Callback Configuration Functions¶

void BrickIMU.setAccelerationPeriod(long period)¶

Parameters:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

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

long BrickIMU.getAccelerationPeriod()¶

Returns:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by setAccelerationPeriod().

void BrickIMU.setMagneticFieldPeriod(long period)¶

Parameters:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

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

long BrickIMU.getMagneticFieldPeriod()¶

Returns:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by setMagneticFieldPeriod().

void BrickIMU.setAngularVelocityPeriod(long period)¶

Parameters:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

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

long BrickIMU.getAngularVelocityPeriod()¶

Returns:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by setAngularVelocityPeriod().

void BrickIMU.setAllDataPeriod(long period)¶

Parameters:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

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

long BrickIMU.getAllDataPeriod()¶

Returns:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by setAllDataPeriod().

void BrickIMU.setOrientationPeriod(long period)¶

Parameters:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

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

long BrickIMU.getOrientationPeriod()¶

Returns:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by setOrientationPeriod().

void BrickIMU.setQuaternionPeriod(long period)¶

Parameters:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

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

long BrickIMU.getQuaternionPeriod()¶

Returns:	period – Type: long, Unit: 1 ms, Range: [0 to 2³² - 1], Default: 0

Returns the period as set by setQuaternionPeriod().

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 BrickIMU.AccelerationCallback¶

Event Object:	x – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] y – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] z – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]

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.

callback BrickIMU.MagneticFieldCallback¶

Event Object:	x – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] y – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] z – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]

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.

callback BrickIMU.AngularVelocityCallback¶

Event Object:	x – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] y – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] z – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750]

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.

callback BrickIMU.AllDataCallback¶

Event Object:

Event Object:	accX – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] accY – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] accZ – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] magX – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] magY – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] magZ – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] angX – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] angY – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] angZ – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750] temperature – Type: short, Unit: 1/100 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

accX – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
accY – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
accZ – Type: short, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
magX – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
magY – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
magZ – Type: short, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
angX – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750]
angY – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750]
angZ – Type: short, Unit: 8/115 °/s, Range: [-28750 to 28750]
temperature – Type: short, Unit: 1/100 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

This callback is triggered periodically with the period that is set by setAllDataPeriod(). The parameters are the acceleration, the magnetic field and the angular velocity for the x, y and z axis as well as the temperature of the IMU Brick.

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.

callback BrickIMU.OrientationCallback¶

Event Object:	roll – Type: short, Unit: 1/100 °, Range: [-18000 to 18000] pitch – Type: short, Unit: 1/100 °, Range: [-18000 to 18000] yaw – Type: short, Unit: 1/100 °, Range: [-18000 to 18000]

This callback is triggered periodically with the period that is set by setOrientationPeriod(). The parameters are the orientation (roll, pitch and yaw) 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.

callback BrickIMU.QuaternionCallback¶

Event Object:	x – Type: float, Range: [-1.0 to 1.0] y – Type: float, Range: [-1.0 to 1.0] z – Type: float, Range: [-1.0 to 1.0] w – Type: float, Range: [-1.0 to 1.0]

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.

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[] BrickIMU.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 BrickIMU.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:

BrickIMU.FUNCTION_LEDS_ON = 8
BrickIMU.FUNCTION_LEDS_OFF = 9
BrickIMU.FUNCTION_SET_ACCELERATION_RANGE = 11
BrickIMU.FUNCTION_SET_MAGNETOMETER_RANGE = 13
BrickIMU.FUNCTION_SET_CONVERGENCE_SPEED = 15
BrickIMU.FUNCTION_SET_CALIBRATION = 17
BrickIMU.FUNCTION_SET_ACCELERATION_PERIOD = 19
BrickIMU.FUNCTION_SET_MAGNETIC_FIELD_PERIOD = 21
BrickIMU.FUNCTION_SET_ANGULAR_VELOCITY_PERIOD = 23
BrickIMU.FUNCTION_SET_ALL_DATA_PERIOD = 25
BrickIMU.FUNCTION_SET_ORIENTATION_PERIOD = 27
BrickIMU.FUNCTION_SET_QUATERNION_PERIOD = 29
BrickIMU.FUNCTION_ORIENTATION_CALCULATION_ON = 37
BrickIMU.FUNCTION_ORIENTATION_CALCULATION_OFF = 38
BrickIMU.FUNCTION_SET_SPITFP_BAUDRATE_CONFIG = 231
BrickIMU.FUNCTION_SET_SPITFP_BAUDRATE = 234
BrickIMU.FUNCTION_ENABLE_STATUS_LED = 238
BrickIMU.FUNCTION_DISABLE_STATUS_LED = 239
BrickIMU.FUNCTION_RESET = 243
BrickIMU.FUNCTION_WRITE_BRICKLET_PLUGIN = 246

void BrickIMU.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.

The following constants are available for this function:

For functionId:

BrickIMU.FUNCTION_LEDS_ON = 8
BrickIMU.FUNCTION_LEDS_OFF = 9
BrickIMU.FUNCTION_SET_ACCELERATION_RANGE = 11
BrickIMU.FUNCTION_SET_MAGNETOMETER_RANGE = 13
BrickIMU.FUNCTION_SET_CONVERGENCE_SPEED = 15
BrickIMU.FUNCTION_SET_CALIBRATION = 17
BrickIMU.FUNCTION_SET_ACCELERATION_PERIOD = 19
BrickIMU.FUNCTION_SET_MAGNETIC_FIELD_PERIOD = 21
BrickIMU.FUNCTION_SET_ANGULAR_VELOCITY_PERIOD = 23
BrickIMU.FUNCTION_SET_ALL_DATA_PERIOD = 25
BrickIMU.FUNCTION_SET_ORIENTATION_PERIOD = 27
BrickIMU.FUNCTION_SET_QUATERNION_PERIOD = 29
BrickIMU.FUNCTION_ORIENTATION_CALCULATION_ON = 37
BrickIMU.FUNCTION_ORIENTATION_CALCULATION_OFF = 38
BrickIMU.FUNCTION_SET_SPITFP_BAUDRATE_CONFIG = 231
BrickIMU.FUNCTION_SET_SPITFP_BAUDRATE = 234
BrickIMU.FUNCTION_ENABLE_STATUS_LED = 238
BrickIMU.FUNCTION_DISABLE_STATUS_LED = 239
BrickIMU.FUNCTION_RESET = 243
BrickIMU.FUNCTION_WRITE_BRICKLET_PLUGIN = 246

void BrickIMU.setResponseExpectedAll(boolean responseExpected)¶

Parameters:	responseExpected – Type: boolean

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

Internal Functions¶

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

BrickIMU.Protocol1BrickletName BrickIMU.getProtocol1BrickletName(char port)¶

Parameters:	port – Type: char, Range: ['a' to 'b']
Return Object:	protocolVersion – 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] name – Type: String, Length: up to 40

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.

void BrickIMU.writeBrickletPlugin(char port, short offset, short[] chunk)¶

Parameters:	port – Type: char, Range: ['a' to 'b'] offset – Type: short, Range: [0 to 255] chunk – Type: short[], Length: 32, Range: [0 to 255]

Writes 32 bytes of firmware to the bricklet attached at the given port. The bytes are written to the position offset * 32.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

short[] BrickIMU.readBrickletPlugin(char port, short offset)¶

Parameters:	port – Type: char, Range: ['a' to 'b'] offset – Type: short, Range: [0 to 255]
Returns:	chunk – Type: short[], Length: 32, Range: [0 to 255]

Reads 32 bytes of firmware from the bricklet attached at the given port. The bytes are read starting at the position offset * 32.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

Constants¶

int BrickIMU.DEVICE_IDENTIFIER¶

This constant is used to identify a IMU Brick.

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 BrickIMU.DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a IMU Brick.