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

Ruby - IMU Brick¶

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

Examples¶

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

Simple¶

Download (example_simple.rb)

#!/usr/bin/env ruby
# -*- ruby encoding: utf-8 -*-

require 'tinkerforge/ip_connection'
require 'tinkerforge/brick_imu'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XXYYZZ' # Change XXYYZZ to the UID of your IMU Brick

ipcon = IPConnection.new # Create IP connection
imu = BrickIMU.new UID, ipcon # Create device object

ipcon.connect HOST, PORT # Connect to brickd
# Don't use device before ipcon is connected

# Get current quaternion as [x, y, z, w]
quaternion = imu.get_quaternion

puts "Quaternion [X]: #{quaternion[0]}"
puts "Quaternion [Y]: #{quaternion[1]}"
puts "Quaternion [Z]: #{quaternion[2]}"
puts "Quaternion [W]: #{quaternion[3]}"

puts 'Press key to exit'
$stdin.gets
ipcon.disconnect

Callback¶

Download (example_callback.rb)

#!/usr/bin/env ruby
# -*- ruby encoding: utf-8 -*-

require 'tinkerforge/ip_connection'
require 'tinkerforge/brick_imu'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XXYYZZ' # Change XXYYZZ to the UID of your IMU Brick

ipcon = IPConnection.new # Create IP connection
imu = BrickIMU.new UID, ipcon # Create device object

ipcon.connect HOST, PORT # Connect to brickd
# Don't use device before ipcon is connected

# Register quaternion callback
imu.register_callback(BrickIMU::CALLBACK_QUATERNION) do |x, y, z, w|
  puts "Quaternion [X]: #{x}"
  puts "Quaternion [Y]: #{y}"
  puts "Quaternion [Z]: #{z}"
  puts "Quaternion [W]: #{w}"
  puts ''
end

# Set period for quaternion callback to 1s (1000ms)
imu.set_quaternion_period 1000

puts 'Press key to exit'
$stdin.gets
ipcon.disconnect

API¶

All functions listed below are thread-safe.

Basic Functions¶

BrickIMU::new(uid, ipcon) → imu¶

Parameters:	uid – Type: str ipcon – Type: IPConnection
Returns:	imu – Type: BrickIMU

Creates an object with the unique device ID uid:

imu = BrickIMU.new 'YOUR_DEVICE_UID', ipcon

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

BrickIMU#get_orientation → [int, int, int]¶

Return Array:	0: roll – Type: int, Unit: 1/100 °, Range: [-18000 to 18000] 1: pitch – Type: int, Unit: 1/100 °, Range: [-18000 to 18000] 2: yaw – Type: int, 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 ::CALLBACK_ORIENTATION callback and set the period with #set_orientation_period.

BrickIMU#get_quaternion → [float, float, float, float]¶

Return Array:	0: x – Type: float, Range: [-1.0 to 1.0] 1: y – Type: float, Range: [-1.0 to 1.0] 2: z – Type: float, Range: [-1.0 to 1.0] 3: w – Type: float, 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 ::CALLBACK_QUATERNION callback and set the period with #set_quaternion_period.

BrickIMU#leds_on → nil¶: Turns the orientation and direction LEDs of the IMU Brick on.

BrickIMU#leds_off → nil¶: Turns the orientation and direction LEDs of the IMU Brick off.

BrickIMU#are_leds_on → bool¶

Returns:	leds – Type: bool, Default: true

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

BrickIMU#set_convergence_speed(speed) → nil¶

Parameters:	speed – Type: int, 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.

BrickIMU#get_convergence_speed → int¶

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

Returns the convergence speed as set by #set_convergence_speed.

Advanced Functions¶

BrickIMU#get_acceleration → [int, int, int]¶

Return Array:	0: x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] 1: y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] 2: z – Type: int, 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 ::CALLBACK_ACCELERATION callback and set the period with #set_acceleration_period.

BrickIMU#get_magnetic_field → [int, int, int]¶

Return Array:	0: x – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] 1: y – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] 2: z – Type: int, 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 ::CALLBACK_MAGNETIC_FIELD callback and set the period with #set_magnetic_field_period.

BrickIMU#get_angular_velocity → [int, int, int]¶

Return Array:	0: x – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750] 1: y – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750] 2: z – Type: int, 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 ::CALLBACK_ANGULAR_VELOCITY callback and set the period with #set_angular_velocity_period.

BrickIMU#get_all_data → [int, int, int, int, int, int, int, int, int, int]¶

Return Array:

Return Array:	0: acc_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] 1: acc_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] 2: acc_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] 3: mag_x – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] 4: mag_y – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] 5: mag_z – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] 6: ang_x – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750] 7: ang_y – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750] 8: ang_z – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750] 9: temperature – Type: int, Unit: 1/100 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

0: acc_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
1: acc_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
2: acc_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
3: mag_x – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
4: mag_y – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
5: mag_z – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
6: ang_x – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750]
7: ang_y – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750]
8: ang_z – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750]
9: temperature – Type: int, Unit: 1/100 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the data from #get_acceleration, #get_magnetic_field and #get_angular_velocity as well as the temperature of the IMU Brick.

If you want to get the data periodically, it is recommended to use the ::CALLBACK_ALL_DATA callback and set the period with #set_all_data_period.

BrickIMU#get_imu_temperature → int¶

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

Returns the temperature of the IMU Brick.

BrickIMU#set_acceleration_range(range) → nil¶

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

Not implemented yet.

BrickIMU#get_acceleration_range → int¶

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

Not implemented yet.

BrickIMU#set_magnetometer_range(range) → nil¶

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

Not implemented yet.

BrickIMU#get_magnetometer_range → int¶

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

Not implemented yet.

BrickIMU#set_calibration(typ, data) → nil¶

Parameters:	typ – Type: int, Range: See constants data – Type: [int, ...], Length: 10, 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:

BrickIMU::CALIBRATION_TYPE_ACCELEROMETER_GAIN = 0
BrickIMU::CALIBRATION_TYPE_ACCELEROMETER_BIAS = 1
BrickIMU::CALIBRATION_TYPE_MAGNETOMETER_GAIN = 2
BrickIMU::CALIBRATION_TYPE_MAGNETOMETER_BIAS = 3
BrickIMU::CALIBRATION_TYPE_GYROSCOPE_GAIN = 4
BrickIMU::CALIBRATION_TYPE_GYROSCOPE_BIAS = 5

BrickIMU#get_calibration(typ) → [int, ...]¶

Parameters:	typ – Type: int, Range: See constants
Returns:	data – Type: [int, ...], Length: 10, Range: [-2¹⁵ to 2¹⁵ - 1]

Returns the calibration for a given type as set by #set_calibration.

The following constants are available for this function:

For typ:

BrickIMU::CALIBRATION_TYPE_ACCELEROMETER_GAIN = 0
BrickIMU::CALIBRATION_TYPE_ACCELEROMETER_BIAS = 1
BrickIMU::CALIBRATION_TYPE_MAGNETOMETER_GAIN = 2
BrickIMU::CALIBRATION_TYPE_MAGNETOMETER_BIAS = 3
BrickIMU::CALIBRATION_TYPE_GYROSCOPE_GAIN = 4
BrickIMU::CALIBRATION_TYPE_GYROSCOPE_BIAS = 5

BrickIMU#orientation_calculation_on → nil¶

Turns the orientation calculation of the IMU Brick on.

As default the calculation is on.

New in version 2.0.2 (Firmware).

BrickIMU#orientation_calculation_off → nil¶

Turns the orientation calculation of the IMU Brick off.

If the calculation is off, #get_orientation 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#is_orientation_calculation_on → bool¶

Returns:	orientation_calculation_on – Type: bool, Default: true

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

New in version 2.0.2 (Firmware).

BrickIMU#set_spitfp_baudrate_config(enable_dynamic_baudrate, minimum_dynamic_baudrate) → nil¶

Parameters:	enable_dynamic_baudrate – Type: bool, Default: true minimum_dynamic_baudrate – Type: int, 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 #set_spitfp_baudrate. If the dynamic baudrate is disabled, the baudrate as set by #set_spitfp_baudrate will be used statically.

New in version 2.3.5 (Firmware).

BrickIMU#get_spitfp_baudrate_config → [bool, int]¶

Return Array:	0: enable_dynamic_baudrate – Type: bool, Default: true 1: minimum_dynamic_baudrate – Type: int, Unit: 1 Bd, Range: [400000 to 2000000], Default: 400000

Returns the baudrate config, see #set_spitfp_baudrate_config.

New in version 2.3.5 (Firmware).

BrickIMU#get_send_timeout_count(communication_method) → int¶

Parameters:	communication_method – Type: int, Range: See constants
Returns:	timeout_count – Type: int, 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 communication_method:

BrickIMU::COMMUNICATION_METHOD_NONE = 0
BrickIMU::COMMUNICATION_METHOD_USB = 1
BrickIMU::COMMUNICATION_METHOD_SPI_STACK = 2
BrickIMU::COMMUNICATION_METHOD_CHIBI = 3
BrickIMU::COMMUNICATION_METHOD_RS485 = 4
BrickIMU::COMMUNICATION_METHOD_WIFI = 5
BrickIMU::COMMUNICATION_METHOD_ETHERNET = 6
BrickIMU::COMMUNICATION_METHOD_WIFI_V2 = 7

New in version 2.3.3 (Firmware).

BrickIMU#set_spitfp_baudrate(bricklet_port, baudrate) → nil¶

Parameters:	bricklet_port – Type: chr, Range: ['a' to 'b'] baudrate – Type: int, 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 #get_spitfp_error_count) you can decrease the baudrate.

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

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#get_spitfp_baudrate(bricklet_port) → int¶

Parameters:	bricklet_port – Type: chr, Range: ['a' to 'b']
Returns:	baudrate – Type: int, Unit: 1 Bd, Range: [400000 to 2000000], Default: 1400000

Returns the baudrate for a given Bricklet port, see #set_spitfp_baudrate.

New in version 2.3.3 (Firmware).

BrickIMU#get_spitfp_error_count(bricklet_port) → [int, int, int, int]¶

Parameters:	bricklet_port – Type: chr, Range: ['a' to 'b']
Return Array:	0: error_count_ack_checksum – Type: int, Range: [0 to 2³² - 1] 1: error_count_message_checksum – Type: int, Range: [0 to 2³² - 1] 2: error_count_frame – Type: int, Range: [0 to 2³² - 1] 3: error_count_overflow – Type: int, 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).

BrickIMU#enable_status_led → nil¶

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#disable_status_led → nil¶

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#is_status_led_enabled → bool¶

Returns:	enabled – Type: bool, Default: true

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

New in version 2.3.1 (Firmware).

BrickIMU#get_chip_temperature → int¶

Returns:	temperature – Type: int, 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.

BrickIMU#reset → nil¶

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#get_identity → [str, str, chr, [int, ...], [int, ...], int]¶

Return Array:

Return Array:	0: uid – Type: str, Length: up to 8 1: connected_uid – Type: str, Length: up to 8 2: position – Type: chr, Range: ['0' to '8'] 3: hardware_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] 4: firmware_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] 5: device_identifier – Type: int, Range: [0 to 2¹⁶ - 1]

0: uid – Type: str, Length: up to 8
1: connected_uid – Type: str, Length: up to 8
2: position – Type: chr, Range: ['0' to '8']
3: hardware_version – Type: [int, ...], Length: 3

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

4: firmware_version – Type: [int, ...], Length: 3

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

5: device_identifier – Type: int, 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¶

BrickIMU#register_callback(callback_id) { |param [, ...]| block } → nil¶

Parameters:	callback_id – Type: int

Registers the given block with the given callback_id.

The available callback IDs with corresponding function signatures are listed below.

BrickIMU#set_acceleration_period(period) → nil¶

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

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

BrickIMU#get_acceleration_period → int¶

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

Returns the period as set by #set_acceleration_period.

BrickIMU#set_magnetic_field_period(period) → nil¶

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

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

BrickIMU#get_magnetic_field_period → int¶

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

Returns the period as set by #set_magnetic_field_period.

BrickIMU#set_angular_velocity_period(period) → nil¶

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

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

BrickIMU#get_angular_velocity_period → int¶

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

Returns the period as set by #set_angular_velocity_period.

BrickIMU#set_all_data_period(period) → nil¶

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

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

BrickIMU#get_all_data_period → int¶

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

Returns the period as set by #set_all_data_period.

BrickIMU#set_orientation_period(period) → nil¶

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

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

BrickIMU#get_orientation_period → int¶

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

Returns the period as set by #set_orientation_period.

BrickIMU#set_quaternion_period(period) → nil¶

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

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

BrickIMU#get_quaternion_period → int¶

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

Returns the period as set by #set_quaternion_period.

Callbacks¶

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the #register_callback function of the device object. The first parameter is the callback ID and the second parameter is a block:

imu.register_callback BrickIMU::CALLBACK_EXAMPLE, do |param|
  puts "#{param}"
end

The available constants with inherent number and type of parameters are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

BrickIMU::CALLBACK_ACCELERATION¶

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

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

BrickIMU::CALLBACK_MAGNETIC_FIELD¶

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

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

BrickIMU::CALLBACK_ANGULAR_VELOCITY¶

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

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

BrickIMU::CALLBACK_ALL_DATA¶

Callback Parameters:

Callback Parameters:	acc_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] acc_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] acc_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1] mag_x – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] mag_y – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] mag_z – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1] ang_x – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750] ang_y – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750] ang_z – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750] temperature – Type: int, Unit: 1/100 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

acc_x – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
acc_y – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
acc_z – Type: int, Unit: 1/1000 gₙ, Range: [-2¹⁵ to 2¹⁵ - 1]
mag_x – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
mag_y – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
mag_z – Type: int, Unit: 1/10 µT, Range: [-2¹⁵ to 2¹⁵ - 1]
ang_x – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750]
ang_y – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750]
ang_z – Type: int, Unit: 8/115 °/s, Range: [-28750 to 28750]
temperature – Type: int, Unit: 1/100 °C, Range: [-2¹⁵ to 2¹⁵ - 1]

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

BrickIMU::CALLBACK_ORIENTATION¶

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

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

BrickIMU::CALLBACK_QUATERNION¶

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

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

BrickIMU#get_api_version → [int, ...]¶

Return Array:	0: api_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, 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.

BrickIMU#get_response_expected(function_id) → bool¶

Parameters:	function_id – Type: int, Range: See constants
Returns:	response_expected – Type: bool

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 #set_response_expected. 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 function_id:

BrickIMU::FUNCTION_LEDS_ON = 8
BrickIMU::FUNCTION_LEDS_OFF = 9
BrickIMU::FUNCTION_SET_ACCELERATION_RANGE = 11
BrickIMU::FUNCTION_SET_MAGNETOMETER_RANGE = 13
BrickIMU::FUNCTION_SET_CONVERGENCE_SPEED = 15
BrickIMU::FUNCTION_SET_CALIBRATION = 17
BrickIMU::FUNCTION_SET_ACCELERATION_PERIOD = 19
BrickIMU::FUNCTION_SET_MAGNETIC_FIELD_PERIOD = 21
BrickIMU::FUNCTION_SET_ANGULAR_VELOCITY_PERIOD = 23
BrickIMU::FUNCTION_SET_ALL_DATA_PERIOD = 25
BrickIMU::FUNCTION_SET_ORIENTATION_PERIOD = 27
BrickIMU::FUNCTION_SET_QUATERNION_PERIOD = 29
BrickIMU::FUNCTION_ORIENTATION_CALCULATION_ON = 37
BrickIMU::FUNCTION_ORIENTATION_CALCULATION_OFF = 38
BrickIMU::FUNCTION_SET_SPITFP_BAUDRATE_CONFIG = 231
BrickIMU::FUNCTION_SET_SPITFP_BAUDRATE = 234
BrickIMU::FUNCTION_ENABLE_STATUS_LED = 238
BrickIMU::FUNCTION_DISABLE_STATUS_LED = 239
BrickIMU::FUNCTION_RESET = 243
BrickIMU::FUNCTION_WRITE_BRICKLET_PLUGIN = 246

BrickIMU#set_response_expected(function_id, response_expected) → nil¶

Parameters:	function_id – Type: int, Range: See constants response_expected – Type: bool

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 function_id:

BrickIMU::FUNCTION_LEDS_ON = 8
BrickIMU::FUNCTION_LEDS_OFF = 9
BrickIMU::FUNCTION_SET_ACCELERATION_RANGE = 11
BrickIMU::FUNCTION_SET_MAGNETOMETER_RANGE = 13
BrickIMU::FUNCTION_SET_CONVERGENCE_SPEED = 15
BrickIMU::FUNCTION_SET_CALIBRATION = 17
BrickIMU::FUNCTION_SET_ACCELERATION_PERIOD = 19
BrickIMU::FUNCTION_SET_MAGNETIC_FIELD_PERIOD = 21
BrickIMU::FUNCTION_SET_ANGULAR_VELOCITY_PERIOD = 23
BrickIMU::FUNCTION_SET_ALL_DATA_PERIOD = 25
BrickIMU::FUNCTION_SET_ORIENTATION_PERIOD = 27
BrickIMU::FUNCTION_SET_QUATERNION_PERIOD = 29
BrickIMU::FUNCTION_ORIENTATION_CALCULATION_ON = 37
BrickIMU::FUNCTION_ORIENTATION_CALCULATION_OFF = 38
BrickIMU::FUNCTION_SET_SPITFP_BAUDRATE_CONFIG = 231
BrickIMU::FUNCTION_SET_SPITFP_BAUDRATE = 234
BrickIMU::FUNCTION_ENABLE_STATUS_LED = 238
BrickIMU::FUNCTION_DISABLE_STATUS_LED = 239
BrickIMU::FUNCTION_RESET = 243
BrickIMU::FUNCTION_WRITE_BRICKLET_PLUGIN = 246

BrickIMU#set_response_expected_all(response_expected) → nil¶

Parameters:	response_expected – Type: bool

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.

BrickIMU#get_protocol1_bricklet_name(port) → [int, [int, ...], str]¶

Parameters:	port – Type: chr, Range: ['a' to 'b']
Return Array:	0: protocol_version – Type: int, Range: [0 to 255] 1: firmware_version – Type: [int, ...], Length: 3 0: major – Type: int, Range: [0 to 255] 1: minor – Type: int, Range: [0 to 255] 2: revision – Type: int, Range: [0 to 255] 2: name – Type: str, 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.

BrickIMU#write_bricklet_plugin(port, offset, chunk) → nil¶

Parameters:	port – Type: chr, Range: ['a' to 'b'] offset – Type: int, Range: [0 to 255] chunk – Type: [int, ...], Length: 32, 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.

BrickIMU#read_bricklet_plugin(port, offset) → [int, ...]¶

Parameters:	port – Type: chr, Range: ['a' to 'b'] offset – Type: int, Range: [0 to 255]
Returns:	chunk – Type: [int, ...], Length: 32, 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¶

BrickIMU::DEVICE_IDENTIFIER¶

This constant is used to identify a IMU Brick.

The #get_identity() function and the IPConnection::CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier 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.