C# - IMU Brick – Tinkerforge

- Getting Started
  - Primer
  - Tutorials
  - FAQ
- Hardware
  - Bricks
  - Bricklets
  - Master Extensions
  - Power Supplies
  - Accessories
  - Timeline
- Software
  - Brick Daemon (brickd)
  - Brick Viewer (brickv)
  - API Bindings
    - C/C++
    - C/C++ (iOS)
    - C#
      - Requirements
      - Installation
      - Testing an Example
      - CLS Compliance
      - API Reference and Examples
        - IP Connection
        - Bricks
          - DC Brick
          - IMU Brick
            - Examples
              - Simple
              - Callback
            - API
              - Basic Functions
              - Advanced Functions
              - Callback Configuration Functions
              - Callbacks
              - Constants
          - Master Brick
          - RED Brick
          - Servo Brick
          - Stepper Brick
        - Bricklets
    - C# (Windows Phone)
    - Delphi/Lazarus
    - Java
    - Java (Android)
    - JavaScript
    - LabVIEW
    - Mathematica
    - MATLAB/Octave
    - Perl
    - PHP
    - Python
    - Ruby
    - Shell
    - Visual Basic .NET
  - Firmwares and Plugins
  - Device Identifier
  - Source Code and Bug Tracking
  - Programming Interface
- Starter Kits
  - Weather Station
  - Hardware Hacking
  - Server Room Monitoring
  - Blinkenlights
  - Internet of Things
  - Camera Slider
- Embedded Boards
  - Raspberry Pi
- Specifications
  - Technical Data
  - TCP/IP Protocol
  - Modbus Protocol
  - Wireshark Dissector

# C# - IMU Brick

This is the description of the C# 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 C# API bindings is part of their general description.

## Examples

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

### Simple

Download (ExampleSimple.cs)

     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

    using Tinkerforge;

    class Example
    {
        private static string HOST = "localhost";
        private static int PORT = 4223;
        private static string UID = "6QGRFq"; // Change to your UID

        static void Main()
        {
            IPConnection ipcon = new IPConnection(); // Create IP connection
            BrickIMU imu = new BrickIMU(UID, ipcon); // Create device object

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

            // Get current quaternion
            float x, y, z, w;
            imu.GetQuaternion(out x, out y, out z, out w);

            System.Console.WriteLine("x: " + x);
            System.Console.WriteLine("y: " + y);
            System.Console.WriteLine("z: " + z);
            System.Console.WriteLine("w: " + w);

            System.Console.WriteLine("Press enter to exit");
            System.Console.ReadLine();
            ipcon.Disconnect();
        }
    }

### Callback

Download (ExampleCallback.cs)

     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
    34
    35
    36
    37

    using Tinkerforge;

    class Example
    {
        private static string HOST = "localhost";
        private static int PORT = 4223;
        private static string UID = "ayQskyoNrCW"; // Change to your UID

        // Quaternion callback
        static void QuaternionCB(BrickIMU sender, float x, float y, float z, float w)
        {
            System.Console.WriteLine("x: " + x);
            System.Console.WriteLine("y: " + y);
            System.Console.WriteLine("z: " + z);
            System.Console.WriteLine("w: " + w);
            System.Console.WriteLine("");
        }

        static void Main()
        {
            IPConnection ipcon = new IPConnection(); // Create IP connection
            BrickIMU imu = new BrickIMU(UID, ipcon); // Create device object

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

            // Set period for quaternion callback to 1s
            imu.SetQuaternionPeriod(1000);

            // Register quaternion callback to QuaternionCB
            imu.Quaternion += QuaternionCB;

            System.Console.WriteLine("Press enter to exit");
            System.Console.ReadLine();
            ipcon.Disconnect();
        }
    }

## API

Generally, every method of the C# bindings that returns a value can throw a `Tinkerforge.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 plugs the device out). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Since C# does not support multiple return values directly, we use the `out` keyword to return multiple values from a method.

The namespace for all Brick/Bricklet bindings and the IPConnection is `Tinkerforge.*`.

All methods listed below are thread-safe.

### Basic Functions

public class `BrickIMU`(String uid, IPConnection ipcon)

  Creates an object with the unique device ID `uid`:

      BrickIMU imu = new BrickIMU("YOUR_DEVICE_UID", ipcon);

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

public void `GetOrientation`(out short roll, out short pitch, out short yaw)

  Returns the current orientation (roll, pitch, yaw) of the IMU Brick as Euler angles in one-hundredth degree. 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 callback `Orientation` and set the period with `SetOrientationPeriod()`.

public void `GetQuaternion`(out float x, out float y, out float z, out float w)

  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 callback `Quaternion` and set the period with `SetQuaternionPeriod()`.

public void `LedsOn`()

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

public void `LedsOff`()

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

public bool `AreLedsOn`()

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

public void `SetConvergenceSpeed`(int speed)

  Sets the convergence speed of the IMU Brick in °/s. 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.

  The default value is 30.

public int `GetConvergenceSpeed`()

  Returns the convergence speed as set by `SetConvergenceSpeed()`.

### Advanced Functions

public void `GetAcceleration`(out short x, out short y, out short z)

  Returns the calibrated acceleration from the accelerometer for the x, y and z axis in mG (G/1000, 1G = 9.80605m/s²).

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

public void `GetMagneticField`(out short x, out short y, out short z)

  Returns the calibrated magnetic field from the magnetometer for the x, y and z axis in mG (Milligauss or Nanotesla).

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

public void `GetAngularVelocity`(out short x, out short y, out short z)

  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 callback `AngularVelocity` and set the period with `SetAngularVelocityPeriod()`.

public void `GetAllData`(out short accX, out short accY, out short accZ, out short magX, out short magY, out short magZ, out short angX, out short angY, out short angZ, out short temperature)

  Returns the data from `GetAcceleration()`, `GetMagneticField()` and `GetAngularVelocity()` as well as the temperature of the IMU Brick.

  The temperature is given in °C/100.

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

public short `GetIMUTemperature`()

  Returns the temperature of the IMU Brick. The temperature is given in °C/100.

public void `SetAccelerationRange`(byte range)

  Not implemented yet.

public byte `GetAccelerationRange`()

  Not implemented yet.

public void `SetMagnetometerRange`(byte range)

  Not implemented yet.

public byte `GetMagnetometerRange`()

  Not implemented yet.

public void `SetCalibration`(byte typ, short[] data)

  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:

  - 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

public short[] `GetCalibration`(byte typ)

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

  The following constants are available for this function:

  - 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

public void `OrientationCalculationOn`()

  Turns the orientation calculation of the IMU Brick on.

  As default the calculation is on.

  New in version 2.0.2 (Firmware).

public void `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).

public bool `IsOrientationCalculationOn`()

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

  New in version 2.0.2 (Firmware).

public byte[] `GetAPIVersion`()

  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.

public bool `GetResponseExpected`(byte functionId)

  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.

public void `SetResponseExpected`(byte functionId, bool responseExpected)

  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:

  - 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_ENABLE_STATUS_LED = 238
  - BrickIMU.FUNCTION_DISABLE_STATUS_LED = 239
  - BrickIMU.FUNCTION_RESET = 243

public void `SetResponseExpectedAll`(bool responseExpected)

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

public void `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).

public void `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).

public bool `IsStatusLEDEnabled`()

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

  New in version 2.3.1 (Firmware).

public void `GetProtocol1BrickletName`(char port, out byte protocolVersion, out byte[] firmwareVersion, out string name)

  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.

public short `GetChipTemperature`()

  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.

public void `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!

public void `GetIdentity`(out string uid, out string connectedUid, out char position, out byte[] hardwareVersion, out byte[] firmwareVersion, out int deviceIdentifier)

  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

public void `SetAccelerationPeriod`(long period)

  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.

public long `GetAccelerationPeriod`()

  Returns the period as set by `SetAccelerationPeriod()`.

public void `SetMagneticFieldPeriod`(long period)

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

public long `GetMagneticFieldPeriod`()

  Returns the period as set by `SetMagneticFieldPeriod()`.

public void `SetAngularVelocityPeriod`(long period)

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

public long `GetAngularVelocityPeriod`()

  Returns the period as set by `SetAngularVelocityPeriod()`.

public void `SetAllDataPeriod`(long period)

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

public long `GetAllDataPeriod`()

  Returns the period as set by `SetAllDataPeriod()`.

public void `SetOrientationPeriod`(long period)

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

public long `GetOrientationPeriod`()

  Returns the period as set by `SetOrientationPeriod()`.

public void `SetQuaternionPeriod`(long period)

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

public long `GetQuaternionPeriod`()

  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 by appending your callback handler to the corresponding event:

    void Callback(BrickIMU sender, int value)
    {
        System.Console.WriteLine("Value: " + value);
    }

    imu.ExampleCallback += Callback;

The available events 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.

public event `Acceleration`(BrickIMU sender, short x, short y, short z)

  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.

public event `MagneticField`(BrickIMU sender, short x, short y, short z)

  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.

public event `AngularVelocity`(BrickIMU sender, short x, short y, short z)

  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.

public event `AllData`(BrickIMU sender, short accX, short accY, short accZ, short magX, short magY, short magZ, short angX, short angY, short angZ, short temperature)

  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.

public event `Orientation`(BrickIMU sender, short roll, short pitch, short yaw)

  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.

public event `Quaternion`(BrickIMU sender, float x, float y, float z, float w)

  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.

### Constants

public int `DEVICE_IDENTIFIER`

  This constant is used to identify a IMU Brick.

  The `GetIdentity()` function and the `EnumerateCallback` callback of the IP Connection have a `deviceIdentifier` parameter to specify the Brick's or Bricklet's type.

The content of this page is licensed under Creative Commons Attribution 3.0 Unported License.