This is the description of the C# API bindings for the IMU Brick. General information and technical specifications for the IMU Brick are summarized in its hardware description.
An installation guide for the C# API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | using System;
using Tinkerforge;
class Example
{
private static string HOST = "localhost";
private static int PORT = 4223;
private static string UID = "XXYYZZ"; // Change XXYYZZ to the UID of your IMU Brick
static void Main()
{
IPConnection ipcon = new IPConnection(); // Create IP connection
BrickIMU imu = new BrickIMU(UID, ipcon); // Create device object
ipcon.Connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Get current quaternion
float x, y, z, w;
imu.GetQuaternion(out x, out y, out z, out w);
Console.WriteLine("Quaternion [X]: " + x);
Console.WriteLine("Quaternion [Y]: " + y);
Console.WriteLine("Quaternion [Z]: " + z);
Console.WriteLine("Quaternion [W]: " + w);
Console.WriteLine("Press enter to exit");
Console.ReadLine();
ipcon.Disconnect();
}
}
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | using System;
using Tinkerforge;
class Example
{
private static string HOST = "localhost";
private static int PORT = 4223;
private static string UID = "XXYYZZ"; // Change XXYYZZ to the UID of your IMU Brick
// Callback function for quaternion callback
static void QuaternionCB(BrickIMU sender, float x, float y, float z, float w)
{
Console.WriteLine("Quaternion [X]: " + x);
Console.WriteLine("Quaternion [Y]: " + y);
Console.WriteLine("Quaternion [Z]: " + z);
Console.WriteLine("Quaternion [W]: " + w);
Console.WriteLine("");
}
static void Main()
{
IPConnection ipcon = new IPConnection(); // Create IP connection
BrickIMU imu = new BrickIMU(UID, ipcon); // Create device object
ipcon.Connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Register quaternion callback to function QuaternionCB
imu.QuaternionCallback += QuaternionCB;
// Set period for quaternion callback to 1s (1000ms)
imu.SetQuaternionPeriod(1000);
Console.WriteLine("Press enter to exit");
Console.ReadLine();
ipcon.Disconnect();
}
}
|
Generally, every method of the C# bindings that returns a value can
throw a Tinkerforge.TimeoutException
. This exception gets thrown if the
device did not respond. If a cable based connection is used, it is
unlikely that this exception gets thrown (assuming nobody plugs the
device out). However, if a wireless connection is used, timeouts will occur
if the distance to the device gets too big.
Since C# does not support multiple return values directly, we use the out
keyword to return multiple values from a method.
The namespace for all Brick/Bricklet bindings and the IPConnection is
Tinkerforge.*
.
All methods listed below are thread-safe.
BrickIMU
(string uid, IPConnection ipcon)¶Parameters: |
|
---|---|
Returns: |
|
Creates an object with the unique device ID uid
:
BrickIMU imu = new BrickIMU("YOUR_DEVICE_UID", ipcon);
This object can then be used after the IP Connection is connected.
BrickIMU.
GetOrientation
(out short roll, out short pitch, out short yaw)¶Output Parameters: |
|
---|
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()
.
BrickIMU.
GetQuaternion
(out float x, out float y, out float z, out float w)¶Output Parameters: |
|
---|
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()
.
BrickIMU.
LedsOn
()¶Turns the orientation and direction LEDs of the IMU Brick on.
BrickIMU.
LedsOff
()¶Turns the orientation and direction LEDs of the IMU Brick off.
BrickIMU.
AreLedsOn
()¶Returns: |
|
---|
Returns true if the orientation and direction LEDs of the IMU Brick are on, false otherwise.
BrickIMU.
SetConvergenceSpeed
(int speed)¶Parameters: |
|
---|
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.
BrickIMU.
GetConvergenceSpeed
()¶Returns: |
|
---|
Returns the convergence speed as set by SetConvergenceSpeed()
.
BrickIMU.
GetAcceleration
(out short x, out short y, out short z)¶Output Parameters: |
|
---|
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()
.
BrickIMU.
GetMagneticField
(out short x, out short y, out short z)¶Output Parameters: |
|
---|
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()
.
BrickIMU.
GetAngularVelocity
(out short x, out short y, out short z)¶Output Parameters: |
|
---|
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()
.
BrickIMU.
GetAllData
(out short accX, out short accY, out short accZ, out short magX, out short magY, out short magZ, out short angX, out short angY, out short angZ, out short temperature)¶Output Parameters: |
|
---|
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()
.
BrickIMU.
GetIMUTemperature
()¶Returns: |
|
---|
Returns the temperature of the IMU Brick.
BrickIMU.
SetAccelerationRange
(byte range)¶Parameters: |
|
---|
Not implemented yet.
BrickIMU.
GetAccelerationRange
()¶Returns: |
|
---|
Not implemented yet.
BrickIMU.
SetMagnetometerRange
(byte range)¶Parameters: |
|
---|
Not implemented yet.
BrickIMU.
GetMagnetometerRange
()¶Returns: |
|
---|
Not implemented yet.
BrickIMU.
SetCalibration
(byte typ, short[] data)¶Parameters: |
|
---|
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:
BrickIMU.
GetCalibration
(byte typ)¶Parameters: |
|
---|---|
Returns: |
|
Returns the calibration for a given type as set by SetCalibration()
.
The following constants are available for this function:
For typ:
BrickIMU.
OrientationCalculationOn
()¶Turns the orientation calculation of the IMU Brick on.
As default the calculation is on.
New in version 2.0.2 (Firmware).
BrickIMU.
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).
BrickIMU.
IsOrientationCalculationOn
()¶Returns: |
|
---|
Returns true if the orientation calculation of the IMU Brick is on, false otherwise.
New in version 2.0.2 (Firmware).
BrickIMU.
SetSPITFPBaudrateConfig
(bool enableDynamicBaudrate, long minimumDynamicBaudrate)¶Parameters: |
|
---|
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).
BrickIMU.
GetSPITFPBaudrateConfig
(out bool enableDynamicBaudrate, out long minimumDynamicBaudrate)¶Output Parameters: |
|
---|
Returns the baudrate config, see SetSPITFPBaudrateConfig()
.
New in version 2.3.5 (Firmware).
BrickIMU.
GetSendTimeoutCount
(byte communicationMethod)¶Parameters: |
|
---|---|
Returns: |
|
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:
New in version 2.3.3 (Firmware).
BrickIMU.
SetSPITFPBaudrate
(char brickletPort, long baudrate)¶Parameters: |
|
---|
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).
BrickIMU.
GetSPITFPBaudrate
(char brickletPort)¶Parameters: |
|
---|---|
Returns: |
|
Returns the baudrate for a given Bricklet port, see SetSPITFPBaudrate()
.
New in version 2.3.3 (Firmware).
BrickIMU.
GetSPITFPErrorCount
(char brickletPort, out long errorCountACKChecksum, out long errorCountMessageChecksum, out long errorCountFrame, out long errorCountOverflow)¶Parameters: |
|
---|---|
Output Parameters: |
|
Returns the error count for the communication between Brick and Bricklet.
The errors are divided into
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).
BrickIMU.
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).
BrickIMU.
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).
BrickIMU.
IsStatusLEDEnabled
()¶Returns: |
|
---|
Returns true if the status LED is enabled, false otherwise.
New in version 2.3.1 (Firmware).
BrickIMU.
GetChipTemperature
()¶Returns: |
|
---|
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.
BrickIMU.
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!
BrickIMU.
GetIdentity
(out string uid, out string connectedUid, out char position, out byte[] hardwareVersion, out byte[] firmwareVersion, out int deviceIdentifier)¶Output Parameters: |
|
---|
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.
BrickIMU.
SetAccelerationPeriod
(long period)¶Parameters: |
|
---|
Sets the period with which the AccelerationCallback
callback is triggered
periodically. A value of 0 turns the callback off.
BrickIMU.
GetAccelerationPeriod
()¶Returns: |
|
---|
Returns the period as set by SetAccelerationPeriod()
.
BrickIMU.
SetMagneticFieldPeriod
(long period)¶Parameters: |
|
---|
Sets the period with which the MagneticFieldCallback
callback is
triggered periodically. A value of 0 turns the callback off.
BrickIMU.
GetMagneticFieldPeriod
()¶Returns: |
|
---|
Returns the period as set by SetMagneticFieldPeriod()
.
BrickIMU.
SetAngularVelocityPeriod
(long period)¶Parameters: |
|
---|
Sets the period with which the AngularVelocityCallback
callback is
triggered periodically. A value of 0 turns the callback off.
BrickIMU.
GetAngularVelocityPeriod
()¶Returns: |
|
---|
Returns the period as set by SetAngularVelocityPeriod()
.
BrickIMU.
SetAllDataPeriod
(long period)¶Parameters: |
|
---|
Sets the period with which the AllDataCallback
callback is triggered
periodically. A value of 0 turns the callback off.
BrickIMU.
GetAllDataPeriod
()¶Returns: |
|
---|
Returns the period as set by SetAllDataPeriod()
.
BrickIMU.
SetOrientationPeriod
(long period)¶Parameters: |
|
---|
Sets the period with which the OrientationCallback
callback is triggered
periodically. A value of 0 turns the callback off.
BrickIMU.
GetOrientationPeriod
()¶Returns: |
|
---|
Returns the period as set by SetOrientationPeriod()
.
BrickIMU.
SetQuaternionPeriod
(long period)¶Parameters: |
|
---|
Sets the period with which the QuaternionCallback
callback is triggered
periodically. A value of 0 turns the callback off.
BrickIMU.
GetQuaternionPeriod
()¶Returns: |
|
---|
Returns the period as set by SetQuaternionPeriod()
.
Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by appending your callback handler to the corresponding event:
void MyCallback(BrickIMU sender, int value)
{
System.Console.WriteLine("Value: " + value);
}
imu.ExampleCallback += MyCallback;
The available events are described below.
Note
Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.
BrickIMU.
AccelerationCallback
(BrickIMU sender, short x, short y, short z)¶Callback Parameters: |
|
---|
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.
MagneticFieldCallback
(BrickIMU sender, short x, short y, short z)¶Callback Parameters: |
|
---|
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.
AngularVelocityCallback
(BrickIMU sender, short x, short y, short z)¶Callback Parameters: |
|
---|
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.
AllDataCallback
(BrickIMU sender, short accX, short accY, short accZ, short magX, short magY, short magZ, short angX, short angY, short angZ, short temperature)¶Callback Parameters: |
|
---|
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.
OrientationCallback
(BrickIMU sender, short roll, short pitch, short yaw)¶Callback Parameters: |
|
---|
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.
QuaternionCallback
(BrickIMU sender, float x, float y, float z, float w)¶Callback Parameters: |
|
---|
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 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.
BrickIMU.
GetAPIVersion
()¶Output Parameters: |
|
---|
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.
BrickIMU.
GetResponseExpected
(byte functionId)¶Parameters: |
|
---|---|
Returns: |
|
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:
BrickIMU.
SetResponseExpected
(byte functionId, bool responseExpected)¶Parameters: |
|
---|
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:
BrickIMU.
SetResponseExpectedAll
(bool responseExpected)¶Parameters: |
|
---|
Changes the response expected flag for all setter and callback configuration functions of this device at once.
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.
BrickIMU.
GetProtocol1BrickletName
(char port, out byte protocolVersion, out byte[] firmwareVersion, out string name)¶Parameters: |
|
---|---|
Output Parameters: |
|
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.
WriteBrickletPlugin
(char port, byte offset, byte[] chunk)¶Parameters: |
|
---|
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.
BrickIMU.
ReadBrickletPlugin
(char port, byte offset)¶Parameters: |
|
---|---|
Returns: |
|
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.
BrickIMU.
DEVICE_IDENTIFIER
¶This constant is used to identify a IMU Brick.
The GetIdentity()
function and the
IPConnection.EnumerateCallback
callback of the IP Connection have a deviceIdentifier
parameter to specify
the Brick's or Bricklet's type.
BrickIMU.
DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a IMU Brick.