Visual Basic .NET - IMU Brick 2.0

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 Visual Basic .NET 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 Visual Basic .NET API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

API

Since Visual Basic .NET does not support multiple return values directly, we use the ByRef keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.

Basic Functions

Class BrickIMUV2(ByVal uid As String, ByVal ipcon As IPConnection)

Creates an object with the unique device ID uid:

Dim imuV2 As New BrickIMUV2("YOUR_DEVICE_UID", ipcon)

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

Sub BrickIMUV2.GetAllData(ByRef acceleration() As Short, ByRef magneticField() As Short, ByRef angularVelocity() As Short, ByRef eulerAngle() As Short, ByRef quaternion() As Short, ByRef linearAcceleration() As Short, ByRef gravityVector() As Short, ByRef temperature As Short, ByRef calibrationStatus As Byte)

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.

  • bit 0-1: Magnetometer
  • bit 2-3: Accelerometer
  • bit 4-5: Gyroscope
  • bit 6-7: System

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 AllData and set the period with SetAllDataPeriod().

Sub BrickIMUV2.LedsOn()

Turns the orientation and direction LEDs of the IMU Brick on.

Sub BrickIMUV2.LedsOff()

Turns the orientation and direction LEDs of the IMU Brick off.

Function BrickIMUV2.AreLedsOn() As Boolean

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

Advanced Functions

Sub BrickIMUV2.GetAcceleration(ByRef x As Short, ByRef y As Short, ByRef z As Short)

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 Acceleration and set the period with SetAccelerationPeriod().

Sub BrickIMUV2.GetMagneticField(ByRef x As Short, ByRef y As Short, ByRef z As Short)

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 MagneticField and set the period with SetMagneticFieldPeriod().

Sub BrickIMUV2.GetAngularVelocity(ByRef x As Short, ByRef y As Short, ByRef z As Short)

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 AngularVelocity and set the period with SetAngularVelocityPeriod().

Function BrickIMUV2.GetTemperature() As Short

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

Sub BrickIMUV2.GetOrientation(ByRef heading As Short, ByRef roll As Short, ByRef pitch As Short)

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:

  • heading: 0° to 360°
  • roll: -90° to +90°
  • pitch: -180° to +180°

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

Sub BrickIMUV2.GetLinearAcceleration(ByRef x As Short, ByRef y As Short, ByRef z As Short)

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 LinearAcceleration and set the period with SetLinearAccelerationPeriod().

Sub BrickIMUV2.GetGravityVector(ByRef x As Short, ByRef y As Short, ByRef z As Short)

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 GravityVector and set the period with SetGravityVectorPeriod().

Sub BrickIMUV2.GetQuaternion(ByRef w As Short, ByRef x As Short, ByRef y As Short, ByRef z As Short)

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 Quaternion and set the period with SetQuaternionPeriod().

Function BrickIMUV2.SaveCalibration() As Boolean

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.

Function BrickIMUV2.GetAPIVersion() As Byte()

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.

Function BrickIMUV2.GetResponseExpected(ByVal functionId As Byte) As 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 send and errors are silently ignored, because they cannot be detected.

See SetResponseExpected() for the list of function ID constants available for this function.

Sub BrickIMUV2.SetResponseExpected(ByVal functionId As Byte, ByVal responseExpected As 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 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:

  • BrickIMUV2.FUNCTION_LEDS_ON = 10
  • BrickIMUV2.FUNCTION_LEDS_OFF = 11
  • BrickIMUV2.FUNCTION_SET_ACCELERATION_PERIOD = 14
  • BrickIMUV2.FUNCTION_SET_MAGNETIC_FIELD_PERIOD = 16
  • BrickIMUV2.FUNCTION_SET_ANGULAR_VELOCITY_PERIOD = 18
  • BrickIMUV2.FUNCTION_SET_TEMPERATURE_PERIOD = 20
  • BrickIMUV2.FUNCTION_SET_ORIENTATION_PERIOD = 22
  • BrickIMUV2.FUNCTION_SET_LINEAR_ACCELERATION_PERIOD = 24
  • BrickIMUV2.FUNCTION_SET_GRAVITY_VECTOR_PERIOD = 26
  • BrickIMUV2.FUNCTION_SET_QUATERNION_PERIOD = 28
  • BrickIMUV2.FUNCTION_SET_ALL_DATA_PERIOD = 30
  • BrickIMUV2.FUNCTION_ENABLE_STATUS_LED = 238
  • BrickIMUV2.FUNCTION_DISABLE_STATUS_LED = 239
  • BrickIMUV2.FUNCTION_RESET = 243
Sub BrickIMUV2.SetResponseExpectedAll(ByVal responseExpected As Boolean)

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

Sub BrickIMUV2.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.

Sub BrickIMUV2.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.

Function BrickIMUV2.IsStatusLEDEnabled() As Boolean

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

Sub BrickIMUV2.GetProtocol1BrickletName(ByVal port As Char, ByRef protocolVersion As Byte, ByRef firmwareVersion() As Byte, ByRef name As String)

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.

Function BrickIMUV2.GetChipTemperature() As Short

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.

Sub BrickIMUV2.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!

Sub BrickIMUV2.GetIdentity(ByRef uid As String, ByRef connectedUid As String, ByRef position As Char, ByRef hardwareVersion() As Byte, ByRef firmwareVersion() As Byte, ByRef deviceIdentifier As Integer)

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.

Callback Configuration Functions

Sub BrickIMUV2.SetAccelerationPeriod(ByVal period As Long)

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

The default value is 0.

Function BrickIMUV2.GetAccelerationPeriod() As Long

Returns the period as set by SetAccelerationPeriod().

Sub BrickIMUV2.SetMagneticFieldPeriod(ByVal period As Long)

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

Function BrickIMUV2.GetMagneticFieldPeriod() As Long

Returns the period as set by SetMagneticFieldPeriod().

Sub BrickIMUV2.SetAngularVelocityPeriod(ByVal period As Long)

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

Function BrickIMUV2.GetAngularVelocityPeriod() As Long

Returns the period as set by SetAngularVelocityPeriod().

Sub BrickIMUV2.SetTemperaturePeriod(ByVal period As Long)

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

Function BrickIMUV2.GetTemperaturePeriod() As Long

Returns the period as set by SetTemperaturePeriod().

Sub BrickIMUV2.SetOrientationPeriod(ByVal period As Long)

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

Function BrickIMUV2.GetOrientationPeriod() As Long

Returns the period as set by SetOrientationPeriod().

Sub BrickIMUV2.SetLinearAccelerationPeriod(ByVal period As Long)

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

Function BrickIMUV2.GetLinearAccelerationPeriod() As Long

Returns the period as set by SetLinearAccelerationPeriod().

Sub BrickIMUV2.SetGravityVectorPeriod(ByVal period As Long)

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

Function BrickIMUV2.GetGravityVectorPeriod() As Long

Returns the period as set by SetGravityVectorPeriod().

Sub BrickIMUV2.SetQuaternionPeriod(ByVal period As Long)

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

Function BrickIMUV2.GetQuaternionPeriod() As Long

Returns the period as set by SetQuaternionPeriod().

Sub BrickIMUV2.SetAllDataPeriod(ByVal period As Long)

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

Function BrickIMUV2.GetAllDataPeriod() As Long

Returns the period as set by SetAllDataPeriod().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by assigning a procedure to an callback property of the device object:

Sub Callback(ByVal sender As BrickIMUV2, ByVal value As Short)
    Console.WriteLine("Value: {0}", value)
End Sub

AddHandler imuV2.Example, AddressOf Callback

The available callback property and their type of parameters 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.

Event BrickIMUV2.Acceleration(ByVal sender As BrickIMUV2, ByVal x As Short, ByVal y As Short, ByVal z As Short)

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.

Event BrickIMUV2.MagneticField(ByVal sender As BrickIMUV2, ByVal x As Short, ByVal y As Short, ByVal z As Short)

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.

Event BrickIMUV2.AngularVelocity(ByVal sender As BrickIMUV2, ByVal x As Short, ByVal y As Short, ByVal z As Short)

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.

Event BrickIMUV2.Temperature(ByVal sender As BrickIMUV2, ByVal temperature As Short)

This callback is triggered periodically with the period that is set by SetTemperaturePeriod(). The parameter is the temperature.

Event BrickIMUV2.LinearAcceleration(ByVal sender As BrickIMUV2, ByVal x As Short, ByVal y As Short, ByVal z As Short)

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.

Event BrickIMUV2.GravityVector(ByVal sender As BrickIMUV2, ByVal x As Short, ByVal y As Short, ByVal z As Short)

This callback is triggered periodically with the period that is set by SetGravityVectorPeriod(). The parameters gravity vector for the x, y and z axis.

Event BrickIMUV2.Orientation(ByVal sender As BrickIMUV2, ByVal heading As Short, ByVal roll As Short, ByVal pitch As Short)

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.

Event BrickIMUV2.Quaternion(ByVal sender As BrickIMUV2, ByVal w As Short, ByVal x As Short, ByVal y As Short, ByVal z As Short)

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.

Event BrickIMUV2.AllData(ByVal sender As BrickIMUV2, ByVal acceleration() As Short, ByVal magneticField() As Short, ByVal angularVelocity() As Short, ByVal eulerAngle() As Short, ByVal quaternion() As Short, ByVal linearAcceleration() As Short, ByVal gravityVector() As Short, ByVal temperature As Short, ByVal calibrationStatus As Byte)

This callback is triggered periodically with the period that is set by SetAllDataPeriod(). The parameters are as for GetAllData().

Constants

Const BrickIMUV2.DEVICE_IDENTIFIER

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.

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