JavaScript - IMU Brick – Tinkerforge

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# JavaScript - IMU Brick

This is the description of the JavaScript 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 JavaScript API bindings is part of their general description.

## Examples

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

### Callback (Node.js)

Download (ExampleCallback.js)

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    var Tinkerforge = require('tinkerforge');

    var HOST = 'localhost';
    var PORT = 4223;
    var UID = '6QFQff'; // Change to your UID

    var ipcon = new Tinkerforge.IPConnection(); // Create IP connection
    var imu = new Tinkerforge.BrickIMU(UID, ipcon); // Create device object

    ipcon.connect(HOST, PORT,
        function(error) {
            console.log('Error: '+error);
        }
    ); // Connect to brickd
    // Don't use device before ipcon is connected

    ipcon.on(Tinkerforge.IPConnection.CALLBACK_CONNECTED,
        function(connectReason) {
            // Set period for quaternion callback to 1s
            imu.setQuaternionPeriod(1000);
        }
    );

    // Register quaternion callback
    imu.on(Tinkerforge.BrickIMU.CALLBACK_QUATERNION,
        // Quaternion callback
        function(x, y, z, w) {
            console.log('x: '+x);
            console.log('y: '+y);
            console.log('z: '+z);
            console.log('w: '+w);
            console.log();
        }
    );

    console.log("Press any key to exit ...");
    process.stdin.on('data',
        function(data) {
            ipcon.disconnect();
            process.exit(0);
        }
    );

### Callback (HTML)

Download (ExampleCallback.html), Test (ExampleCallback.html)

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    <!DOCTYPE html>
    <html>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <head>
            <title>Tinkerforge | JavaScript Example</title>
        </head>
        <body>
            <div style="text-align:center;">
                <h1>IMU Brick Callback Example</h1>
                <p>
                    <input value="localhost" id="host" type="text" size="20">:
                    <input value="4280" id="port" type="text" size="5">,
                    <input value="uid" id="uid" type="text" size="5">
                    <input value="Start Example" id="start" type="button" onclick="startExample();">
                </p>
                <p>
                    <textarea id="text" cols="80" rows="24" style="resize:none;"
                              >Press "Start Example" to begin ...</textarea>
                </p>
            <div>
            <script src="./Tinkerforge.js" type='text/javascript'></script>
            <script type='text/javascript'>
                var ipcon;
                var textArea = document.getElementById("text");
                function startExample() {
                    textArea.value = "";
                    var HOST = document.getElementById("host").value;
                    var PORT = parseInt(document.getElementById("port").value);
                    var UID = document.getElementById("uid").value;
                    if(ipcon !== undefined) {
                        ipcon.disconnect();
                    }
                    ipcon = new Tinkerforge.IPConnection(); // Create IP connection
                    var imu = new Tinkerforge.BrickIMU(UID, ipcon); // Create device object
                    ipcon.connect(HOST, PORT,
                        function(error) {
                            textArea.value += 'Error: '+error+ '\n';
                        }
                    ); // Connect to brickd
                    // Don't use device before ipcon is connected

                    ipcon.on(Tinkerforge.IPConnection.CALLBACK_CONNECTED,
                        function(connectReason) {
                            // Set period for quaternion callback to 1s
                            imu.setQuaternionPeriod(1000);
                        }
                    );
                    // Register quaternion callback
                    imu.on(Tinkerforge.BrickIMU.CALLBACK_QUATERNION,
                        // Quaternion callback
                        function(x, y, z, w) {
                            textArea.value += 'x: '+x+'\n';
                            textArea.value += 'y: '+y+'\n';
                            textArea.value += 'z: '+z+'\n';
                            textArea.value += 'w: '+w+'\n';
                            textArea.value += '\n';
                            textArea.scrollTop = textArea.scrollHeight;
                        }
                    );
                }
            </script>
        </body>
    </html>

## API

Generally, every method of the JavaScript bindings can take two optional parameters, `returnCallback` and `errorCallback`. These are two user defined callback functions. The `returnCallback` is called with the return values as parameters, if the method returns something. The `errorCallback` is called with an error code in case of an error. The error code can be one of the following values:

- IPConnection.ERROR_ALREADY_CONNECTED = 11
- IPConnection.ERROR_NOT_CONNECTED = 12
- IPConnection.ERROR_CONNECT_FAILED = 13
- IPConnection.ERROR_INVALID_FUNCTION_ID = 21
- IPConnection.ERROR_TIMEOUT = 31
- IPConnection.ERROR_INVALID_PARAMETER = 41
- IPConnection.ERROR_FUNCTION_NOT_SUPPORTED = 42
- IPConnection.ERROR_UNKNOWN_ERROR = 43

The namespace for the JavaScript bindings is `Tinkerforge.*`.

### Basic Functions

new `BrickIMU`(uid, ipcon)

  Parameters:

  - uid -- string
  - ipcon -- IPConnection

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

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

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

`BrickIMU.``getOrientation`([returnCallback][, errorCallback])

  Callback:

  - roll -- int
  - pitch -- int
  - yaw -- int

  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 `CALLBACK_ORIENTATION` and set the period with `setOrientationPeriod()`.

`BrickIMU.``getQuaternion`([returnCallback][, errorCallback])

  Callback:

  - x -- float
  - y -- float
  - z -- float
  - w -- float

  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 `CALLBACK_QUATERNION` and set the period with `setQuaternionPeriod()`.

`BrickIMU.``ledsOn`([returnCallback][, errorCallback])

  Callback: | undefined

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

`BrickIMU.``ledsOff`([returnCallback][, errorCallback])

  Callback: | undefined

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

`BrickIMU.``areLedsOn`([returnCallback][, errorCallback])

  Callback:

  - leds -- boolean

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

`BrickIMU.``setConvergenceSpeed`(speed[, returnCallback][, errorCallback])

  Parameters:

  - speed -- int

  Callback: | undefined

  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.

`BrickIMU.``getConvergenceSpeed`([returnCallback][, errorCallback])

  Callback:

  - speed -- int

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

### Advanced Functions

`BrickIMU.``getAcceleration`([returnCallback][, errorCallback])

  Callback:

  - x -- int
  - y -- int
  - z -- int

  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 `CALLBACK_ACCELERATION` and set the period with `setAccelerationPeriod()`.

`BrickIMU.``getMagneticField`([returnCallback][, errorCallback])

  Callback:

  - x -- int
  - y -- int
  - z -- int

  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 `CALLBACK_MAGNETIC_FIELD` and set the period with `setMagneticFieldPeriod()`.

`BrickIMU.``getAngularVelocity`([returnCallback][, errorCallback])

  Callback:

  - x -- int
  - y -- int
  - z -- int

  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 `CALLBACK_ANGULAR_VELOCITY` and set the period with `setAngularVelocityPeriod()`.

`BrickIMU.``getAllData`([returnCallback][, errorCallback])

  Callback:

  - accX -- int
  - accY -- int
  - accZ -- int
  - magX -- int
  - magY -- int
  - magZ -- int
  - angX -- int
  - angY -- int
  - angZ -- int
  - temperature -- int

  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 `CALLBACK_ALL_DATA` and set the period with `setAllDataPeriod()`.

`BrickIMU.``getIMUTemperature`([returnCallback][, errorCallback])

  Callback:

  - temperature -- int

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

`BrickIMU.``setAccelerationRange`(range[, returnCallback][, errorCallback])

  Parameters:

  - range -- int

  Callback: | undefined

  Not implemented yet.

`BrickIMU.``getAccelerationRange`([returnCallback][, errorCallback])

  Callback:

  - range -- int

  Not implemented yet.

`BrickIMU.``setMagnetometerRange`(range[, returnCallback][, errorCallback])

  Parameters:

  - range -- int

  Callback: | undefined

  Not implemented yet.

`BrickIMU.``getMagnetometerRange`([returnCallback][, errorCallback])

  Callback:

  - range -- int

  Not implemented yet.

`BrickIMU.``setCalibration`(typ, data[, returnCallback][, errorCallback])

  Parameters:

  - typ -- int
  - data -- [int, int, int, int, int, int, int, int, int, int]

  Callback: | undefined

  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

`BrickIMU.``getCalibration`(typ[, returnCallback][, errorCallback])

  Parameters:

  - typ -- int

  Callback:

  - data -- [int, int, int, int, int, int, int, int, int, int]

  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

`BrickIMU.``orientationCalculationOn`([returnCallback][, errorCallback])

  Callback: | undefined

  Turns the orientation calculation of the IMU Brick on.

  As default the calculation is on.

  New in version 2.0.2 (Firmware).

`BrickIMU.``orientationCalculationOff`([returnCallback][, errorCallback])

  Callback: | undefined

  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).

`BrickIMU.``isOrientationCalculationOn`([returnCallback][, errorCallback])

  Callback:

  - orientationCalculationOn -- boolean

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

  New in version 2.0.2 (Firmware).

`BrickIMU.``getAPIVersion`()

  Return type: | [int, int, int]

  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.

`BrickIMU.``getResponseExpected`(functionId[, errorCallback])

  Parameters:

  - functionId -- int

  Return 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 send and errors are silently ignored, because they cannot be detected.

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

`BrickIMU.``setResponseExpected`(functionId, responseExpected[, errorCallback])

  Parameters:

  - functionId -- int
  - responseExpected -- 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:

  - 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

`BrickIMU.``setResponseExpectedAll`(responseExpected)

  Parameters:

  - responseExpected -- boolean

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

`BrickIMU.``enableStatusLED`([returnCallback][, errorCallback])

  Callback: | undefined

  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).

`BrickIMU.``disableStatusLED`([returnCallback][, errorCallback])

  Callback: | undefined

  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).

`BrickIMU.``isStatusLEDEnabled`([returnCallback][, errorCallback])

  Callback:

  - enabled -- boolean

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

  New in version 2.3.1 (Firmware).

`BrickIMU.``getProtocol1BrickletName`(port[, returnCallback][, errorCallback])

  Parameters:

  - port -- char

  Callback:

  - protocolVersion -- int
  - firmwareVersion -- [int, int, int]
  - name -- 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.

`BrickIMU.``getChipTemperature`([returnCallback][, errorCallback])

  Callback:

  - temperature -- int

  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.

`BrickIMU.``reset`([returnCallback][, errorCallback])

  Callback: | undefined

  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.``getIdentity`([returnCallback][, errorCallback])

  Callback:

  - uid -- string
  - connectedUid -- string
  - position -- char
  - hardwareVersion -- [int, int, int]
  - firmwareVersion -- [int, int, int]
  - deviceIdentifier -- int

  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

`BrickIMU.``on`(id, callback)

  Parameters:

  - id -- int
  - callback -- function

  Registers a callback with ID id to the function callback. The available IDs with corresponding function signatures are listed below.

`BrickIMU.``setAccelerationPeriod`(period[, returnCallback][, errorCallback])

  Parameters:

  - period -- int

  Callback: | undefined

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

  The default value is 0.

`BrickIMU.``getAccelerationPeriod`([returnCallback][, errorCallback])

  Callback:

  - period -- int

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

`BrickIMU.``setMagneticFieldPeriod`(period[, returnCallback][, errorCallback])

  Parameters:

  - period -- int

  Callback: | undefined

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

`BrickIMU.``getMagneticFieldPeriod`([returnCallback][, errorCallback])

  Callback:

  - period -- int

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

`BrickIMU.``setAngularVelocityPeriod`(period[, returnCallback][, errorCallback])

  Parameters:

  - period -- int

  Callback: | undefined

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

`BrickIMU.``getAngularVelocityPeriod`([returnCallback][, errorCallback])

  Callback:

  - period -- int

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

`BrickIMU.``setAllDataPeriod`(period[, returnCallback][, errorCallback])

  Parameters:

  - period -- int

  Callback: | undefined

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

`BrickIMU.``getAllDataPeriod`([returnCallback][, errorCallback])

  Callback:

  - period -- int

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

`BrickIMU.``setOrientationPeriod`(period[, returnCallback][, errorCallback])

  Parameters:

  - period -- int

  Callback: | undefined

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

`BrickIMU.``getOrientationPeriod`([returnCallback][, errorCallback])

  Callback:

  - period -- int

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

`BrickIMU.``setQuaternionPeriod`(period[, returnCallback][, errorCallback])

  Parameters:

  - period -- int

  Callback: | undefined

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

`BrickIMU.``getQuaternionPeriod`([returnCallback][, errorCallback])

  Callback:

  - period -- int

  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 the `on()` function of the device object. The first parameter is the callback ID and the second parameter the callback function:

    imu.on(BrickIMU.CALLBACK_EXAMPLE,
        function (param) {
            console.log(param);
        }
    );

The available constants with inherent number and 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.

`BrickIMU.``CALLBACK_ACCELERATION`

  Parameters:

  - x -- int
  - y -- int
  - z -- int

  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.

`BrickIMU.``CALLBACK_MAGNETIC_FIELD`

  Parameters:

  - x -- int
  - y -- int
  - z -- int

  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.

`BrickIMU.``CALLBACK_ANGULAR_VELOCITY`

  Parameters:

  - x -- int
  - y -- int
  - z -- int

  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.

`BrickIMU.``CALLBACK_ALL_DATA`

  Parameters:

  - accX -- int
  - accY -- int
  - accZ -- int
  - magX -- int
  - magY -- int
  - magZ -- int
  - angX -- int
  - angY -- int
  - angZ -- int
  - temperature -- int

  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.

`BrickIMU.``CALLBACK_ORIENTATION`

  Parameters:

  - roll -- int
  - pitch -- int
  - yaw -- int

  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.

`BrickIMU.``CALLBACK_QUATERNION`

  Parameters:

  - x -- float
  - y -- float
  - z -- float
  - w -- float

  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

`BrickIMU.``DEVICE_IDENTIFIER`

  This constant is used to identify a IMU Brick.

  The `getIdentity()` function and the `CALLBACK_ENUMERATE` callback of the IP Connection have a `device_identifier` parameter to specify the Brick's or Bricklet's type.

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