Go - IMU Brick

This is the description of the Go 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 Go API bindings is part of their general description. Additional documentation can be found on godoc.org.

Examples

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

Simple

Download (example_simple.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/imu_brick"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
)

const ADDR string = "localhost:4223"
const UID string = "XXYYZZ" // Change XXYYZZ to the UID of your IMU Brick.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    imu, _ := imu_brick.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    // Get current quaternion.
    x, y, z, w, _ := imu.GetQuaternion()

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

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

Callback

Download (example_callback.go)

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package main

import (
    "fmt"
    "github.com/Tinkerforge/go-api-bindings/imu_brick"
    "github.com/Tinkerforge/go-api-bindings/ipconnection"
)

const ADDR string = "localhost:4223"
const UID string = "XXYYZZ" // Change XXYYZZ to the UID of your IMU Brick.

func main() {
    ipcon := ipconnection.New()
    defer ipcon.Close()
    imu, _ := imu_brick.New(UID, &ipcon) // Create device object.

    ipcon.Connect(ADDR) // Connect to brickd.
    defer ipcon.Disconnect()
    // Don't use device before ipcon is connected.

    imu.RegisterQuaternionCallback(func(x float32, y float32, z float32, w float32) {
        fmt.Printf("Quaternion [X]: %f\n", x)
        fmt.Printf("Quaternion [Y]: %f\n", y)
        fmt.Printf("Quaternion [Z]: %f\n", z)
        fmt.Printf("Quaternion [W]: %f\n", w)
        fmt.Println()
    })

    // Set period for quaternion receiver to 1s (1000ms).
    imu.SetQuaternionPeriod(1000)

    fmt.Print("Press enter to exit.")
    fmt.Scanln()
}

API

The IMU Brick API is defined in the package github.com/Tinkerforge/go-api-bindings/imu_brick

Nearly every function of the Go bindings can return an ipconnection.DeviceError, implementing the error interface. The error can have one of the following values:

  • ipconnection.DeviceErrorSuccess = 0
  • ipconnection.DeviceErrorInvalidParameter = 1
  • ipconnection.DeviceErrorFunctionNotSupported = 2
  • ipconnection.DeviceErrorUnknownError = 3

which correspond to the values returned from Bricks and Bricklets.

All functions listed below are thread-safe.

Basic Functions

func imu_brick.New(uid string, ipcon *IPConnection) (device IMUBrick, err error)
Parameters:
  • uid – Type: string
  • ipcon – Type: *IPConnection
Returns:
  • device – Type: IMUBrick
  • err – Type: error

Creates a new IMUBrick object with the unique device ID uid and adds it to the IPConnection ipcon:

device, err := imu_brick.New("YOUR_DEVICE_UID", &ipcon)

This device object can be used after the IPConnection has been connected.

func (*IMUBrick) GetOrientation() (roll int16, pitch int16, yaw int16, err error)
Returns:
  • roll – Type: int16, Unit: 1/100 °, Range: [-18000 to 18000]
  • pitch – Type: int16, Unit: 1/100 °, Range: [-18000 to 18000]
  • yaw – Type: int16, Unit: 1/100 °, Range: [-18000 to 18000]
  • err – Type: error

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().

func (*IMUBrick) GetQuaternion() (x float32, y float32, z float32, w float32, err error)
Returns:
  • x – Type: float32, Range: [-1.0 to 1.0]
  • y – Type: float32, Range: [-1.0 to 1.0]
  • z – Type: float32, Range: [-1.0 to 1.0]
  • w – Type: float32, Range: [-1.0 to 1.0]
  • err – Type: error

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().

func (*IMUBrick) LedsOn() (err error)
Returns:
  • err – Type: error

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

func (*IMUBrick) LedsOff() (err error)
Returns:
  • err – Type: error

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

func (*IMUBrick) AreLedsOn() (leds bool, err error)
Returns:
  • leds – Type: bool, Default: true
  • err – Type: error

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

func (*IMUBrick) SetConvergenceSpeed(speed uint16) (err error)
Parameters:
  • speed – Type: uint16, Unit: 1 °/s, Range: [0 to 216 - 1], Default: 30
Returns:
  • err – Type: error

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.

func (*IMUBrick) GetConvergenceSpeed() (speed uint16, err error)
Returns:
  • speed – Type: uint16, Unit: 1 °/s, Range: [0 to 216 - 1], Default: 30
  • err – Type: error

Returns the convergence speed as set by SetConvergenceSpeed().

Advanced Functions

func (*IMUBrick) GetAcceleration() (x int16, y int16, z int16, err error)
Returns:
  • x – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • y – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • z – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • err – Type: error

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().

func (*IMUBrick) GetMagneticField() (x int16, y int16, z int16, err error)
Returns:
  • x – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • y – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • z – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • err – Type: error

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().

func (*IMUBrick) GetAngularVelocity() (x int16, y int16, z int16, err error)
Returns:
  • x – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • y – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • z – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • err – Type: error

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().

func (*IMUBrick) GetAllData() (accX int16, accY int16, accZ int16, magX int16, magY int16, magZ int16, angX int16, angY int16, angZ int16, temperature int16, err error)
Returns:
  • accX – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • accY – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • accZ – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • magX – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • magY – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • magZ – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • angX – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • angY – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • angZ – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • temperature – Type: int16, Unit: 1/100 °C, Range: [-215 to 215 - 1]
  • err – Type: error

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().

func (*IMUBrick) GetIMUTemperature() (temperature int16, err error)
Returns:
  • temperature – Type: int16, Unit: 1/100 °C, Range: [-215 to 215 - 1]
  • err – Type: error

Returns the temperature of the IMU Brick.

func (*IMUBrick) SetAccelerationRange(range_ uint8) (err error)
Parameters:
  • range – Type: uint8, Range: [0 to 255]
Returns:
  • err – Type: error

Not implemented yet.

func (*IMUBrick) GetAccelerationRange() (range_ uint8, err error)
Returns:
  • range – Type: uint8, Range: [0 to 255]
  • err – Type: error

Not implemented yet.

func (*IMUBrick) SetMagnetometerRange(range_ uint8) (err error)
Parameters:
  • range – Type: uint8, Range: [0 to 255]
Returns:
  • err – Type: error

Not implemented yet.

func (*IMUBrick) GetMagnetometerRange() (range_ uint8, err error)
Returns:
  • range – Type: uint8, Range: [0 to 255]
  • err – Type: error

Not implemented yet.

func (*IMUBrick) SetCalibration(typ uint8, data [10]int16) (err error)
Parameters:
  • typ – Type: uint8, Range: See constants
  • data – Type: [10]int16, Range: [-215 to 215 - 1]
Returns:
  • err – Type: error

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:

  • imu_brick.CalibrationTypeAccelerometerGain = 0
  • imu_brick.CalibrationTypeAccelerometerBias = 1
  • imu_brick.CalibrationTypeMagnetometerGain = 2
  • imu_brick.CalibrationTypeMagnetometerBias = 3
  • imu_brick.CalibrationTypeGyroscopeGain = 4
  • imu_brick.CalibrationTypeGyroscopeBias = 5
func (*IMUBrick) GetCalibration(typ uint8) (data [10]int16, err error)
Parameters:
  • typ – Type: uint8, Range: See constants
Returns:
  • data – Type: [10]int16, Range: [-215 to 215 - 1]
  • err – Type: error

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

The following constants are available for this function:

For typ:

  • imu_brick.CalibrationTypeAccelerometerGain = 0
  • imu_brick.CalibrationTypeAccelerometerBias = 1
  • imu_brick.CalibrationTypeMagnetometerGain = 2
  • imu_brick.CalibrationTypeMagnetometerBias = 3
  • imu_brick.CalibrationTypeGyroscopeGain = 4
  • imu_brick.CalibrationTypeGyroscopeBias = 5
func (*IMUBrick) OrientationCalculationOn() (err error)
Returns:
  • err – Type: error

Turns the orientation calculation of the IMU Brick on.

As default the calculation is on.

New in version 2.0.2 (Firmware).

func (*IMUBrick) OrientationCalculationOff() (err error)
Returns:
  • err – Type: error

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).

func (*IMUBrick) IsOrientationCalculationOn() (orientationCalculationOn bool, err error)
Returns:
  • orientationCalculationOn – Type: bool, Default: true
  • err – Type: error

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

New in version 2.0.2 (Firmware).

func (*IMUBrick) SetSPITFPBaudrateConfig(enableDynamicBaudrate bool, minimumDynamicBaudrate uint32) (err error)
Parameters:
  • enableDynamicBaudrate – Type: bool, Default: true
  • minimumDynamicBaudrate – Type: uint32, Unit: 1 Bd, Range: [400000 to 2000000], Default: 400000
Returns:
  • err – Type: error

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).

func (*IMUBrick) GetSPITFPBaudrateConfig() (enableDynamicBaudrate bool, minimumDynamicBaudrate uint32, err error)
Returns:
  • enableDynamicBaudrate – Type: bool, Default: true
  • minimumDynamicBaudrate – Type: uint32, Unit: 1 Bd, Range: [400000 to 2000000], Default: 400000
  • err – Type: error

Returns the baudrate config, see SetSPITFPBaudrateConfig().

New in version 2.3.5 (Firmware).

func (*IMUBrick) GetSendTimeoutCount(communicationMethod uint8) (timeoutCount uint32, err error)
Parameters:
  • communicationMethod – Type: uint8, Range: See constants
Returns:
  • timeoutCount – Type: uint32, Range: [0 to 232 - 1]
  • err – Type: error

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:

  • imu_brick.CommunicationMethodNone = 0
  • imu_brick.CommunicationMethodUSB = 1
  • imu_brick.CommunicationMethodSPIStack = 2
  • imu_brick.CommunicationMethodChibi = 3
  • imu_brick.CommunicationMethodRS485 = 4
  • imu_brick.CommunicationMethodWIFI = 5
  • imu_brick.CommunicationMethodEthernet = 6
  • imu_brick.CommunicationMethodWIFIV2 = 7

New in version 2.3.3 (Firmware).

func (*IMUBrick) SetSPITFPBaudrate(brickletPort rune, baudrate uint32) (err error)
Parameters:
  • brickletPort – Type: rune, Range: ['a' to 'b']
  • baudrate – Type: uint32, Unit: 1 Bd, Range: [400000 to 2000000], Default: 1400000
Returns:
  • err – Type: error

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 you applications we recommend to not change the baudrate.

New in version 2.3.3 (Firmware).

func (*IMUBrick) GetSPITFPBaudrate(brickletPort rune) (baudrate uint32, err error)
Parameters:
  • brickletPort – Type: rune, Range: ['a' to 'b']
Returns:
  • baudrate – Type: uint32, Unit: 1 Bd, Range: [400000 to 2000000], Default: 1400000
  • err – Type: error

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

New in version 2.3.3 (Firmware).

func (*IMUBrick) GetSPITFPErrorCount(brickletPort rune) (errorCountACKChecksum uint32, errorCountMessageChecksum uint32, errorCountFrame uint32, errorCountOverflow uint32, err error)
Parameters:
  • brickletPort – Type: rune, Range: ['a' to 'b']
Returns:
  • errorCountACKChecksum – Type: uint32, Range: [0 to 232 - 1]
  • errorCountMessageChecksum – Type: uint32, Range: [0 to 232 - 1]
  • errorCountFrame – Type: uint32, Range: [0 to 232 - 1]
  • errorCountOverflow – Type: uint32, Range: [0 to 232 - 1]
  • err – Type: error

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).

func (*IMUBrick) EnableStatusLED() (err error)
Returns:
  • err – Type: error

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).

func (*IMUBrick) DisableStatusLED() (err error)
Returns:
  • err – Type: error

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).

func (*IMUBrick) IsStatusLEDEnabled() (enabled bool, err error)
Returns:
  • enabled – Type: bool, Default: true
  • err – Type: error

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

New in version 2.3.1 (Firmware).

func (*IMUBrick) GetChipTemperature() (temperature int16, err error)
Returns:
  • temperature – Type: int16, Unit: 1/10 °C, Range: [-215 to 215 - 1]
  • err – Type: error

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.

func (*IMUBrick) Reset() (err error)
Returns:
  • err – Type: error

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!

func (*IMUBrick) GetIdentity() (uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)
Returns:
  • uid – Type: string, Length: up to 8
  • connectedUid – Type: string, Length: up to 8
  • position – Type: rune, Range: ['0' to '8']
  • hardwareVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • firmwareVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • deviceIdentifier – Type: uint16, Range: [0 to 216 - 1]
  • err – Type: error

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

func (*IMUBrick) SetAccelerationPeriod(period uint32) (err error)
Parameters:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:
  • err – Type: error

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

func (*IMUBrick) GetAccelerationPeriod() (period uint32, err error)
Returns:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • err – Type: error

Returns the period as set by SetAccelerationPeriod().

func (*IMUBrick) SetMagneticFieldPeriod(period uint32) (err error)
Parameters:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:
  • err – Type: error

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

func (*IMUBrick) GetMagneticFieldPeriod() (period uint32, err error)
Returns:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • err – Type: error

Returns the period as set by SetMagneticFieldPeriod().

func (*IMUBrick) SetAngularVelocityPeriod(period uint32) (err error)
Parameters:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:
  • err – Type: error

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

func (*IMUBrick) GetAngularVelocityPeriod() (period uint32, err error)
Returns:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • err – Type: error

Returns the period as set by SetAngularVelocityPeriod().

func (*IMUBrick) SetAllDataPeriod(period uint32) (err error)
Parameters:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:
  • err – Type: error

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

func (*IMUBrick) GetAllDataPeriod() (period uint32, err error)
Returns:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • err – Type: error

Returns the period as set by SetAllDataPeriod().

func (*IMUBrick) SetOrientationPeriod(period uint32) (err error)
Parameters:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:
  • err – Type: error

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

func (*IMUBrick) GetOrientationPeriod() (period uint32, err error)
Returns:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • err – Type: error

Returns the period as set by SetOrientationPeriod().

func (*IMUBrick) SetQuaternionPeriod(period uint32) (err error)
Parameters:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
Returns:
  • err – Type: error

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

func (*IMUBrick) GetQuaternionPeriod() (period uint32, err error)
Returns:
  • period – Type: uint32, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • err – Type: error

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 corresponding Register*Callback function, which returns a unique callback ID. This ID can be used to deregister the callback later with the corresponding Deregister*Callback function.

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.

func (*IMUBrick) RegisterAccelerationCallback(func(x int16, y int16, z int16)) (registrationId uint64)
Callback Parameters:
  • x – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • y – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • z – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
Returns:
  • registrationId – Type: uint64

This callback is triggered periodically with the period that is set by SetAccelerationPeriod(). The callback parameters are the acceleration for the x, y and z axis.

func (*IMUBrick) RegisterMagneticFieldCallback(func(x int16, y int16, z int16)) (registrationId uint64)
Callback Parameters:
  • x – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • y – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • z – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
Returns:
  • registrationId – Type: uint64

This callback is triggered periodically with the period that is set by SetMagneticFieldPeriod(). The callback parameters are the magnetic field for the x, y and z axis.

func (*IMUBrick) RegisterAngularVelocityCallback(func(x int16, y int16, z int16)) (registrationId uint64)
Callback Parameters:
  • x – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • y – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • z – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
Returns:
  • registrationId – Type: uint64

This callback is triggered periodically with the period that is set by SetAngularVelocityPeriod(). The callback parameters are the angular velocity for the x, y and z axis.

func (*IMUBrick) RegisterAllDataCallback(func(accX int16, accY int16, accZ int16, magX int16, magY int16, magZ int16, angX int16, angY int16, angZ int16, temperature int16)) (registrationId uint64)
Callback Parameters:
  • accX – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • accY – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • accZ – Type: int16, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1]
  • magX – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • magY – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • magZ – Type: int16, Unit: 1/10 µT, Range: [-215 to 215 - 1]
  • angX – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • angY – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • angZ – Type: int16, Unit: 8/115 °/s, Range: [-28750 to 28750]
  • temperature – Type: int16, Unit: 1/100 °C, Range: [-215 to 215 - 1]
Returns:
  • registrationId – Type: uint64

This callback is triggered periodically with the period that is set by SetAllDataPeriod(). The callback 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.

func (*IMUBrick) RegisterOrientationCallback(func(roll int16, pitch int16, yaw int16)) (registrationId uint64)
Callback Parameters:
  • roll – Type: int16, Unit: 1/100 °, Range: [-18000 to 18000]
  • pitch – Type: int16, Unit: 1/100 °, Range: [-18000 to 18000]
  • yaw – Type: int16, Unit: 1/100 °, Range: [-18000 to 18000]
Returns:
  • registrationId – Type: uint64

This callback is triggered periodically with the period that is set by SetOrientationPeriod(). The callback parameters are the orientation (roll, pitch and yaw) of the IMU Brick in Euler angles. See GetOrientation() for details.

func (*IMUBrick) RegisterQuaternionCallback(func(x float32, y float32, z float32, w float32)) (registrationId uint64)
Callback Parameters:
  • x – Type: float32, Range: [-1.0 to 1.0]
  • y – Type: float32, Range: [-1.0 to 1.0]
  • z – Type: float32, Range: [-1.0 to 1.0]
  • w – Type: float32, Range: [-1.0 to 1.0]
Returns:
  • registrationId – Type: uint64

This callback is triggered periodically with the period that is set by SetQuaternionPeriod(). The callback parameters are the orientation (x, y, z, w) of the IMU Brick in quaternions. See GetQuaternion() for details.

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.

func (*IMUBrick) GetAPIVersion() (apiVersion [3]uint8, err error)
Returns:
  • apiVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • err – Type: error

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.

func (*IMUBrick) GetResponseExpected(functionId uint8) (responseExpected bool, err error)
Parameters:
  • functionId – Type: uint8, Range: See constants
Returns:
  • responseExpected – Type: bool
  • err – Type: error

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:

  • imu_brick.FunctionLedsOn = 8
  • imu_brick.FunctionLedsOff = 9
  • imu_brick.FunctionSetAccelerationRange = 11
  • imu_brick.FunctionSetMagnetometerRange = 13
  • imu_brick.FunctionSetConvergenceSpeed = 15
  • imu_brick.FunctionSetCalibration = 17
  • imu_brick.FunctionSetAccelerationPeriod = 19
  • imu_brick.FunctionSetMagneticFieldPeriod = 21
  • imu_brick.FunctionSetAngularVelocityPeriod = 23
  • imu_brick.FunctionSetAllDataPeriod = 25
  • imu_brick.FunctionSetOrientationPeriod = 27
  • imu_brick.FunctionSetQuaternionPeriod = 29
  • imu_brick.FunctionOrientationCalculationOn = 37
  • imu_brick.FunctionOrientationCalculationOff = 38
  • imu_brick.FunctionSetSPITFPBaudrateConfig = 231
  • imu_brick.FunctionSetSPITFPBaudrate = 234
  • imu_brick.FunctionEnableStatusLED = 238
  • imu_brick.FunctionDisableStatusLED = 239
  • imu_brick.FunctionReset = 243
  • imu_brick.FunctionWriteBrickletPlugin = 246
func (*IMUBrick) SetResponseExpected(functionId uint8, responseExpected bool) (err error)
Parameters:
  • functionId – Type: uint8, Range: See constants
  • responseExpected – Type: bool
Returns:
  • err – Type: error

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.

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:

  • imu_brick.FunctionLedsOn = 8
  • imu_brick.FunctionLedsOff = 9
  • imu_brick.FunctionSetAccelerationRange = 11
  • imu_brick.FunctionSetMagnetometerRange = 13
  • imu_brick.FunctionSetConvergenceSpeed = 15
  • imu_brick.FunctionSetCalibration = 17
  • imu_brick.FunctionSetAccelerationPeriod = 19
  • imu_brick.FunctionSetMagneticFieldPeriod = 21
  • imu_brick.FunctionSetAngularVelocityPeriod = 23
  • imu_brick.FunctionSetAllDataPeriod = 25
  • imu_brick.FunctionSetOrientationPeriod = 27
  • imu_brick.FunctionSetQuaternionPeriod = 29
  • imu_brick.FunctionOrientationCalculationOn = 37
  • imu_brick.FunctionOrientationCalculationOff = 38
  • imu_brick.FunctionSetSPITFPBaudrateConfig = 231
  • imu_brick.FunctionSetSPITFPBaudrate = 234
  • imu_brick.FunctionEnableStatusLED = 238
  • imu_brick.FunctionDisableStatusLED = 239
  • imu_brick.FunctionReset = 243
  • imu_brick.FunctionWriteBrickletPlugin = 246
func (*IMUBrick) SetResponseExpectedAll(responseExpected bool) (err error)
Parameters:
  • responseExpected – Type: bool
Returns:
  • err – Type: error

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.

func (*IMUBrick) GetProtocol1BrickletName(port rune) (protocolVersion uint8, firmwareVersion [3]uint8, name string, err error)
Parameters:
  • port – Type: rune, Range: ['a' to 'b']
Returns:
  • protocolVersion – Type: uint8, Range: [0 to 255]
  • firmwareVersion – Type: [3]uint8
    • 0: major – Type: uint8, Range: [0 to 255]
    • 1: minor – Type: uint8, Range: [0 to 255]
    • 2: revision – Type: uint8, Range: [0 to 255]
  • name – Type: string, Length: up to 40
  • err – Type: error

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.

func (*IMUBrick) WriteBrickletPlugin(port rune, offset uint8, chunk [32]uint8) (err error)
Parameters:
  • port – Type: rune, Range: ['a' to 'b']
  • offset – Type: uint8, Range: [0 to 255]
  • chunk – Type: [32]uint8, Range: [0 to 255]
Returns:
  • err – Type: error

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.

func (*IMUBrick) ReadBrickletPlugin(port rune, offset uint8) (chunk [32]uint8, err error)
Parameters:
  • port – Type: rune, Range: ['a' to 'b']
  • offset – Type: uint8, Range: [0 to 255]
Returns:
  • chunk – Type: [32]uint8, Range: [0 to 255]
  • err – Type: error

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

imu_brick.DeviceIdentifier

This constant is used to identify a IMU Brick.

The GetIdentity() function and the (*IPConnection) RegisterEnumerateCallback callback of the IPConnection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

imu_brick.DeviceDisplayName

This constant represents the human readable name of a IMU Brick.