Software / API Bindings / Delphi/Lazarus / API Reference and Examples / Bricks (Discontinued) / IMU Brick

Delphi/Lazarus - IMU Brick¶

This is the description of the Delphi/Lazarus 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 Delphi/Lazarus API bindings is part of their general description.

Examples¶

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

Simple¶

Download (ExampleSimple.pas)

program ExampleSimple;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickIMU;

type
  TExample = class
  private
    ipcon: TIPConnection;
    imu: TBrickIMU;
  public
    procedure Execute;
  end;

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

var
  e: TExample;

procedure TExample.Execute;
var x, y, z, w: single;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  imu := TBrickIMU.Create(UID, ipcon);

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

  { Get current quaternion }
  imu.GetQuaternion(x, y, z, w);

  WriteLn(Format('Quaternion [X]: %f', [x]));
  WriteLn(Format('Quaternion [Y]: %f', [y]));
  WriteLn(Format('Quaternion [Z]: %f', [z]));
  WriteLn(Format('Quaternion [W]: %f', [w]));

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Callback¶

Download (ExampleCallback.pas)

program ExampleCallback;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickIMU;

type
  TExample = class
  private
    ipcon: TIPConnection;
    imu: TBrickIMU;
  public
    procedure QuaternionCB(sender: TBrickIMU; const x: single; const y: single;
                           const z: single; const w: single);
    procedure Execute;
  end;

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

var
  e: TExample;

{ Callback procedure for quaternion callback }
procedure TExample.QuaternionCB(sender: TBrickIMU; const x: single; const y: single;
                                const z: single; const w: single);
begin
  WriteLn(Format('Quaternion [X]: %f', [x]));
  WriteLn(Format('Quaternion [Y]: %f', [y]));
  WriteLn(Format('Quaternion [Z]: %f', [z]));
  WriteLn(Format('Quaternion [W]: %f', [w]));
  WriteLn('');
end;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  imu := TBrickIMU.Create(UID, ipcon);

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

  { Register quaternion callback to procedure QuaternionCB }
  imu.OnQuaternion := {$ifdef FPC}@{$endif}QuaternionCB;

  { Set period for quaternion callback to 1s (1000ms) }
  imu.SetQuaternionPeriod(1000);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

API¶

Since Delphi does not support multiple return values directly, we use the out keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.

Basic Functions¶

constructor TBrickIMU.Create(const uid: string; ipcon: TIPConnection)¶

Parameters:	uid – Type: string ipcon – Type: TIPConnection
Returns:	imu – Type: TBrickIMU

Creates an object with the unique device ID uid:

imu := TBrickIMU.Create('YOUR_DEVICE_UID', ipcon);

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

procedure TBrickIMU.GetOrientation(out roll: smallint; out pitch: smallint; out yaw: smallint)¶

Output Parameters:	roll – Type: smallint, Unit: 1/100 °, Range: [-18000 to 18000] pitch – Type: smallint, Unit: 1/100 °, Range: [-18000 to 18000] yaw – Type: smallint, Unit: 1/100 °, Range: [-18000 to 18000]

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

We recommend that you use quaternions instead.

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

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

procedure TBrickIMU.GetQuaternion(out x: single; out y: single; out z: single; out w: single)¶

Output Parameters:	x – Type: single, Range: [-1.0 to 1.0] y – Type: single, Range: [-1.0 to 1.0] z – Type: single, Range: [-1.0 to 1.0] w – Type: single, Range: [-1.0 to 1.0]

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

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

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

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

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

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

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

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

If you want to get the quaternions periodically, it is recommended to use the OnQuaternion callback and set the period with SetQuaternionPeriod.

procedure TBrickIMU.LedsOn¶: Turns the orientation and direction LEDs of the IMU Brick on.

procedure TBrickIMU.LedsOff¶: Turns the orientation and direction LEDs of the IMU Brick off.

function TBrickIMU.AreLedsOn: boolean¶

Returns:	leds – Type: boolean, Default: true

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

procedure TBrickIMU.SetConvergenceSpeed(const speed: word)¶

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

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

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

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

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

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

function TBrickIMU.GetConvergenceSpeed: word¶

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

Returns the convergence speed as set by SetConvergenceSpeed.

Advanced Functions¶

procedure TBrickIMU.GetAcceleration(out x: smallint; out y: smallint; out z: smallint)¶

Output Parameters:	x – Type: smallint, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] y – Type: smallint, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] z – Type: smallint, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]

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

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

procedure TBrickIMU.GetMagneticField(out x: smallint; out y: smallint; out z: smallint)¶

Output Parameters:	x – Type: smallint, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] y – Type: smallint, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] z – Type: smallint, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]

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

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

procedure TBrickIMU.GetAngularVelocity(out x: smallint; out y: smallint; out z: smallint)¶

Output Parameters:	x – Type: smallint, Unit: 8/115 °/s, Range: [-28750 to 28750] y – Type: smallint, Unit: 8/115 °/s, Range: [-28750 to 28750] z – Type: smallint, Unit: 8/115 °/s, Range: [-28750 to 28750]

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

If you want to get the angular velocity periodically, it is recommended to use the OnAngularVelocity callback and set the period with SetAngularVelocityPeriod.

procedure TBrickIMU.GetAllData(out accX: smallint; out accY: smallint; out accZ: smallint; out magX: smallint; out magY: smallint; out magZ: smallint; out angX: smallint; out angY: smallint; out angZ: smallint; out temperature: smallint)¶

Output Parameters:

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

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

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

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

function TBrickIMU.GetIMUTemperature: smallint¶

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

Returns the temperature of the IMU Brick.

procedure TBrickIMU.SetAccelerationRange(const range: byte)¶

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

Not implemented yet.

function TBrickIMU.GetAccelerationRange: byte¶

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

Not implemented yet.

procedure TBrickIMU.SetMagnetometerRange(const range: byte)¶

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

Not implemented yet.

function TBrickIMU.GetMagnetometerRange: byte¶

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

Not implemented yet.

procedure TBrickIMU.SetCalibration(const typ: byte; const data: array [0..9] of smallint)¶

Parameters:	typ – Type: byte, Range: See constants data – Type: array [0..9] of smallint, Range: [-2¹⁵ to 2¹⁵ - 1]

There are several different types that can be calibrated:

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

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

new_value = (bias + orig_value) * gain_mul / gain_div

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

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

Note

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

The following constants are available for this function:

For typ:

BRICK_IMU_CALIBRATION_TYPE_ACCELEROMETER_GAIN = 0
BRICK_IMU_CALIBRATION_TYPE_ACCELEROMETER_BIAS = 1
BRICK_IMU_CALIBRATION_TYPE_MAGNETOMETER_GAIN = 2
BRICK_IMU_CALIBRATION_TYPE_MAGNETOMETER_BIAS = 3
BRICK_IMU_CALIBRATION_TYPE_GYROSCOPE_GAIN = 4
BRICK_IMU_CALIBRATION_TYPE_GYROSCOPE_BIAS = 5

function TBrickIMU.GetCalibration(const typ: byte): array [0..9] of smallint¶

Parameters:	typ – Type: byte, Range: See constants
Returns:	data – Type: array [0..9] of smallint, Range: [-2¹⁵ to 2¹⁵ - 1]

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

The following constants are available for this function:

For typ:

BRICK_IMU_CALIBRATION_TYPE_ACCELEROMETER_GAIN = 0
BRICK_IMU_CALIBRATION_TYPE_ACCELEROMETER_BIAS = 1
BRICK_IMU_CALIBRATION_TYPE_MAGNETOMETER_GAIN = 2
BRICK_IMU_CALIBRATION_TYPE_MAGNETOMETER_BIAS = 3
BRICK_IMU_CALIBRATION_TYPE_GYROSCOPE_GAIN = 4
BRICK_IMU_CALIBRATION_TYPE_GYROSCOPE_BIAS = 5

procedure TBrickIMU.OrientationCalculationOn¶

Turns the orientation calculation of the IMU Brick on.

As default the calculation is on.

New in version 2.0.2 (Firmware).

procedure TBrickIMU.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).

function TBrickIMU.IsOrientationCalculationOn: boolean¶

Returns:	orientationCalculationOn – Type: boolean, Default: true

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

New in version 2.0.2 (Firmware).

procedure TBrickIMU.SetSPITFPBaudrateConfig(const enableDynamicBaudrate: boolean; const minimumDynamicBaudrate: longword)¶

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

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

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

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

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

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

New in version 2.3.5 (Firmware).

procedure TBrickIMU.GetSPITFPBaudrateConfig(out enableDynamicBaudrate: boolean; out minimumDynamicBaudrate: longword)¶

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

Returns the baudrate config, see SetSPITFPBaudrateConfig.

New in version 2.3.5 (Firmware).

function TBrickIMU.GetSendTimeoutCount(const communicationMethod: byte): longword¶

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

Returns the timeout count for the different communication methods.

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

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

The following constants are available for this function:

For communicationMethod:

BRICK_IMU_COMMUNICATION_METHOD_NONE = 0
BRICK_IMU_COMMUNICATION_METHOD_USB = 1
BRICK_IMU_COMMUNICATION_METHOD_SPI_STACK = 2
BRICK_IMU_COMMUNICATION_METHOD_CHIBI = 3
BRICK_IMU_COMMUNICATION_METHOD_RS485 = 4
BRICK_IMU_COMMUNICATION_METHOD_WIFI = 5
BRICK_IMU_COMMUNICATION_METHOD_ETHERNET = 6
BRICK_IMU_COMMUNICATION_METHOD_WIFI_V2 = 7

New in version 2.3.3 (Firmware).

procedure TBrickIMU.SetSPITFPBaudrate(const brickletPort: char; const baudrate: longword)¶

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

Sets the baudrate for a specific Bricklet port.

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

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

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

New in version 2.3.3 (Firmware).

function TBrickIMU.GetSPITFPBaudrate(const brickletPort: char): longword¶

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

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

New in version 2.3.3 (Firmware).

procedure TBrickIMU.GetSPITFPErrorCount(const brickletPort: char; out errorCountACKChecksum: longword; out errorCountMessageChecksum: longword; out errorCountFrame: longword; out errorCountOverflow: longword)¶

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

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

The errors are divided into

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

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

New in version 2.3.3 (Firmware).

procedure TBrickIMU.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).

procedure TBrickIMU.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).

function TBrickIMU.IsStatusLEDEnabled: boolean¶

Returns:	enabled – Type: boolean, Default: true

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

New in version 2.3.1 (Firmware).

function TBrickIMU.GetChipTemperature: smallint¶

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

Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has an accuracy of ±15%. Practically it is only useful as an indicator for temperature changes.

procedure TBrickIMU.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!

procedure TBrickIMU.GetIdentity(out uid: string; out connectedUid: string; out position: char; out hardwareVersion: array [0..2] of byte; out firmwareVersion: array [0..2] of byte; out deviceIdentifier: word)¶

Output Parameters:

Output Parameters:	uid – Type: string, Length: up to 8 connectedUid – Type: string, Length: up to 8 position – Type: char, Range: ['0' to '8'] hardwareVersion – Type: array [0..2] of byte 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255] firmwareVersion – Type: array [0..2] of byte 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255] deviceIdentifier – Type: word, Range: [0 to 2¹⁶ - 1]

uid – Type: string, Length: up to 8
connectedUid – Type: string, Length: up to 8
position – Type: char, Range: ['0' to '8']
hardwareVersion – Type: array [0..2] of byte

0: major – Type: byte, Range: [0 to 255]
1: minor – Type: byte, Range: [0 to 255]
2: revision – Type: byte, Range: [0 to 255]

firmwareVersion – Type: array [0..2] of byte

0: major – Type: byte, Range: [0 to 255]
1: minor – Type: byte, Range: [0 to 255]
2: revision – Type: byte, Range: [0 to 255]

deviceIdentifier – Type: word, Range: [0 to 2¹⁶ - 1]

Returns the UID, the UID where the Brick is connected to, the position, the hardware and firmware version as well as the device identifier.

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

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

Callback Configuration Functions¶

procedure TBrickIMU.SetAccelerationPeriod(const period: longword)¶

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

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

function TBrickIMU.GetAccelerationPeriod: longword¶

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

Returns the period as set by SetAccelerationPeriod.

procedure TBrickIMU.SetMagneticFieldPeriod(const period: longword)¶

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

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

function TBrickIMU.GetMagneticFieldPeriod: longword¶

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

Returns the period as set by SetMagneticFieldPeriod.

procedure TBrickIMU.SetAngularVelocityPeriod(const period: longword)¶

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

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

function TBrickIMU.GetAngularVelocityPeriod: longword¶

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

Returns the period as set by SetAngularVelocityPeriod.

procedure TBrickIMU.SetAllDataPeriod(const period: longword)¶

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

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

function TBrickIMU.GetAllDataPeriod: longword¶

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

Returns the period as set by SetAllDataPeriod.

procedure TBrickIMU.SetOrientationPeriod(const period: longword)¶

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

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

function TBrickIMU.GetOrientationPeriod: longword¶

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

Returns the period as set by SetOrientationPeriod.

procedure TBrickIMU.SetQuaternionPeriod(const period: longword)¶

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

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

function TBrickIMU.GetQuaternionPeriod: longword¶

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

Returns the period as set by SetQuaternionPeriod.

Callbacks¶

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

procedure TExample.MyCallback(sender: TBrickIMU; const value: longint);
begin
  WriteLn(Format('Value: %d', [value]));
end;

imu.OnExample := {$ifdef FPC}@{$endif}example.MyCallback;

The available callback properties and their parameter types 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.

property TBrickIMU.OnAcceleration¶

procedure(sender: TBrickIMU; const x: smallint; const y: smallint; const z: smallint) of object;

Callback Parameters:	sender – Type: TBrickIMU x – Type: smallint, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] y – Type: smallint, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] z – Type: smallint, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]

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

property TBrickIMU.OnMagneticField¶

procedure(sender: TBrickIMU; const x: smallint; const y: smallint; const z: smallint) of object;

Callback Parameters:	sender – Type: TBrickIMU x – Type: smallint, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] y – Type: smallint, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] z – Type: smallint, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]

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

property TBrickIMU.OnAngularVelocity¶

procedure(sender: TBrickIMU; const x: smallint; const y: smallint; const z: smallint) of object;

Callback Parameters:	sender – Type: TBrickIMU x – Type: smallint, Unit: 8/115 °/s, Range: [-28750 to 28750] y – Type: smallint, Unit: 8/115 °/s, Range: [-28750 to 28750] z – Type: smallint, Unit: 8/115 °/s, Range: [-28750 to 28750]

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

property TBrickIMU.OnAllData¶

procedure(sender: TBrickIMU; const accX: smallint; const accY: smallint; const accZ: smallint; const magX: smallint; const magY: smallint; const magZ: smallint; const angX: smallint; const angY: smallint; const angZ: smallint; const temperature: smallint) of object;

Callback Parameters:

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

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

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

property TBrickIMU.OnOrientation¶

procedure(sender: TBrickIMU; const roll: smallint; const pitch: smallint; const yaw: smallint) of object;

Callback Parameters:	sender – Type: TBrickIMU roll – Type: smallint, Unit: 1/100 °, Range: [-18000 to 18000] pitch – Type: smallint, Unit: 1/100 °, Range: [-18000 to 18000] yaw – Type: smallint, Unit: 1/100 °, Range: [-18000 to 18000]

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

property TBrickIMU.OnQuaternion¶

procedure(sender: TBrickIMU; const x: single; const y: single; const z: single; const w: single) of object;

Callback Parameters:	sender – Type: TBrickIMU x – Type: single, Range: [-1.0 to 1.0] y – Type: single, Range: [-1.0 to 1.0] z – Type: single, Range: [-1.0 to 1.0] w – Type: single, Range: [-1.0 to 1.0]

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

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.

function TBrickIMU.GetAPIVersion: array [0..2] of byte¶

Output Parameters:	apiVersion – Type: array [0..2] of byte 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255]

Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

function TBrickIMU.GetResponseExpected(const functionId: byte): boolean¶

Parameters:	functionId – Type: byte, Range: See constants
Returns:	responseExpected – Type: boolean

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by SetResponseExpected. For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

BRICK_IMU_FUNCTION_LEDS_ON = 8
BRICK_IMU_FUNCTION_LEDS_OFF = 9
BRICK_IMU_FUNCTION_SET_ACCELERATION_RANGE = 11
BRICK_IMU_FUNCTION_SET_MAGNETOMETER_RANGE = 13
BRICK_IMU_FUNCTION_SET_CONVERGENCE_SPEED = 15
BRICK_IMU_FUNCTION_SET_CALIBRATION = 17
BRICK_IMU_FUNCTION_SET_ACCELERATION_PERIOD = 19
BRICK_IMU_FUNCTION_SET_MAGNETIC_FIELD_PERIOD = 21
BRICK_IMU_FUNCTION_SET_ANGULAR_VELOCITY_PERIOD = 23
BRICK_IMU_FUNCTION_SET_ALL_DATA_PERIOD = 25
BRICK_IMU_FUNCTION_SET_ORIENTATION_PERIOD = 27
BRICK_IMU_FUNCTION_SET_QUATERNION_PERIOD = 29
BRICK_IMU_FUNCTION_ORIENTATION_CALCULATION_ON = 37
BRICK_IMU_FUNCTION_ORIENTATION_CALCULATION_OFF = 38
BRICK_IMU_FUNCTION_SET_SPITFP_BAUDRATE_CONFIG = 231
BRICK_IMU_FUNCTION_SET_SPITFP_BAUDRATE = 234
BRICK_IMU_FUNCTION_ENABLE_STATUS_LED = 238
BRICK_IMU_FUNCTION_DISABLE_STATUS_LED = 239
BRICK_IMU_FUNCTION_RESET = 243
BRICK_IMU_FUNCTION_WRITE_BRICKLET_PLUGIN = 246

procedure TBrickIMU.SetResponseExpected(const functionId: byte; const responseExpected: boolean)¶

Parameters:	functionId – Type: byte, Range: See constants responseExpected – Type: boolean

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

The following constants are available for this function:

For functionId:

BRICK_IMU_FUNCTION_LEDS_ON = 8
BRICK_IMU_FUNCTION_LEDS_OFF = 9
BRICK_IMU_FUNCTION_SET_ACCELERATION_RANGE = 11
BRICK_IMU_FUNCTION_SET_MAGNETOMETER_RANGE = 13
BRICK_IMU_FUNCTION_SET_CONVERGENCE_SPEED = 15
BRICK_IMU_FUNCTION_SET_CALIBRATION = 17
BRICK_IMU_FUNCTION_SET_ACCELERATION_PERIOD = 19
BRICK_IMU_FUNCTION_SET_MAGNETIC_FIELD_PERIOD = 21
BRICK_IMU_FUNCTION_SET_ANGULAR_VELOCITY_PERIOD = 23
BRICK_IMU_FUNCTION_SET_ALL_DATA_PERIOD = 25
BRICK_IMU_FUNCTION_SET_ORIENTATION_PERIOD = 27
BRICK_IMU_FUNCTION_SET_QUATERNION_PERIOD = 29
BRICK_IMU_FUNCTION_ORIENTATION_CALCULATION_ON = 37
BRICK_IMU_FUNCTION_ORIENTATION_CALCULATION_OFF = 38
BRICK_IMU_FUNCTION_SET_SPITFP_BAUDRATE_CONFIG = 231
BRICK_IMU_FUNCTION_SET_SPITFP_BAUDRATE = 234
BRICK_IMU_FUNCTION_ENABLE_STATUS_LED = 238
BRICK_IMU_FUNCTION_DISABLE_STATUS_LED = 239
BRICK_IMU_FUNCTION_RESET = 243
BRICK_IMU_FUNCTION_WRITE_BRICKLET_PLUGIN = 246

procedure TBrickIMU.SetResponseExpectedAll(const responseExpected: boolean)¶

Parameters:	responseExpected – Type: boolean

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

Internal Functions¶

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

procedure TBrickIMU.GetProtocol1BrickletName(const port: char; out protocolVersion: byte; out firmwareVersion: array [0..2] of byte; out name: string)¶

Parameters:	port – Type: char, Range: ['a' to 'b']
Output Parameters:	protocolVersion – Type: byte, Range: [0 to 255] firmwareVersion – Type: array [0..2] of byte 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255] name – Type: string, Length: up to 40

Returns the firmware and protocol version and the name of the Bricklet for a given port.

This functions sole purpose is to allow automatic flashing of v1.x.y Bricklet plugins.

procedure TBrickIMU.WriteBrickletPlugin(const port: char; const offset: byte; const chunk: array [0..31] of byte)¶

Parameters:	port – Type: char, Range: ['a' to 'b'] offset – Type: byte, Range: [0 to 255] chunk – Type: array [0..31] of byte, Range: [0 to 255]

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

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

function TBrickIMU.ReadBrickletPlugin(const port: char; const offset: byte): array [0..31] of byte¶

Parameters:	port – Type: char, Range: ['a' to 'b'] offset – Type: byte, Range: [0 to 255]
Returns:	chunk – Type: array [0..31] of byte, Range: [0 to 255]

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

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

Constants¶

const BRICK_IMU_DEVICE_IDENTIFIER¶

This constant is used to identify a IMU Brick.

The GetIdentity function and the TIPConnection.OnEnumerate callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

const BRICK_IMU_DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a IMU Brick.