Ruby - Motorized Linear Poti Bricklet

This is the description of the Ruby API bindings for the Motorized Linear Poti Bricklet. General information and technical specifications for the Motorized Linear Poti Bricklet 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)

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

require 'tinkerforge/ip_connection'
require 'tinkerforge/bricklet_motorized_linear_poti'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XYZ' # Change XYZ to the UID of your Motorized Linear Poti Bricklet

ipcon = IPConnection.new # Create IP connection
mlp = BrickletMotorizedLinearPoti.new UID, ipcon # Create device object

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

# Get current position
position = mlp.get_position
puts "Position: #{position}" # Range: 0 to 100

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

Callback

Download (example_callback.rb)

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

require 'tinkerforge/ip_connection'
require 'tinkerforge/bricklet_motorized_linear_poti'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XYZ' # Change XYZ to the UID of your Motorized Linear Poti Bricklet

ipcon = IPConnection.new # Create IP connection
mlp = BrickletMotorizedLinearPoti.new UID, ipcon # Create device object

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

# Register position callback
mlp.register_callback(BrickletMotorizedLinearPoti::CALLBACK_POSITION) do |position|
  puts "Position: #{position}" # Range: 0 to 100
end

# Set period for position callback to 0.05s (50ms) without a threshold
mlp.set_position_callback_configuration 50, false, 'x', 0, 0

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

Motor

Download (example_motor.rb)

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

require 'tinkerforge/ip_connection'
require 'tinkerforge/bricklet_motorized_linear_poti'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XYZ' # Change XYZ to the UID of your Motorized Linear Poti Bricklet

ipcon = IPConnection.new # Create IP connection
mlp = BrickletMotorizedLinearPoti.new UID, ipcon # Create device object

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

# Register position reached callback
mlp.register_callback(BrickletMotorizedLinearPoti::CALLBACK_POSITION_REACHED) do |position|
  puts "Position: #{position}" # Range: 0 to 100
end

# Move slider smooth to the middle
mlp.set_motor_position 50, BrickletMotorizedLinearPoti::DRIVE_MODE_SMOOTH, false

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

API

All methods listed below are thread-safe.

Basic Functions

BrickletMotorizedLinearPoti::new(uid, ipcon) → motorized_linear_poti
Parameters:
  • uid -- str
  • ipcon -- IPConnection

Creates an object with the unique device ID uid:

motorized_linear_poti = BrickletMotorizedLinearPoti.new 'YOUR_DEVICE_UID', ipcon

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

BrickletMotorizedLinearPoti#get_position → int

Returns the position of the linear potentiometer. The value is between 0 (slider down) and 100 (slider up).

If you want to get the value periodically, it is recommended to use the ::CALLBACK_POSITION callback. You can set the callback configuration with #set_position_callback_configuration.

BrickletMotorizedLinearPoti#set_motor_position(position, drive_mode, hold_position) → nil
Parameters:
  • position -- int
  • drive_mode -- int
  • hold_position -- bool

Sets the position of the potentiometer. The motorized potentiometer will immediately start to approach the position. Depending on the chosen drive mode, the position will either be reached as fast as possible or in a slow but smooth motion.

The position has to be between 0 (slider down) and 100 (slider up).

If you set the hold position parameter to true, the position will automatically be retained. If a user changes the position of the potentiometer, it will automatically drive back to the original set point.

If the hold position parameter is set to false, the potentiometer can be changed again by the user as soon as the set point was reached once.

The following constants are available for this function:

  • BrickletMotorizedLinearPoti::DRIVE_MODE_FAST = 0
  • BrickletMotorizedLinearPoti::DRIVE_MODE_SMOOTH = 1
BrickletMotorizedLinearPoti#get_motor_position → [int, int, bool, bool]

Returns the last motor position as set by #set_motor_position. This is not the current position (use #get_position to get the current position). This is the last used set point and configuration.

The position reached parameter is true if the position has been reached at one point. The position may have been changed again in the meantime by the user.

The following constants are available for this function:

  • BrickletMotorizedLinearPoti::DRIVE_MODE_FAST = 0
  • BrickletMotorizedLinearPoti::DRIVE_MODE_SMOOTH = 1

The returned array has the values position, drive_mode, hold_position and position_reached.

Advanced Functions

BrickletMotorizedLinearPoti#calibrate → nil

Starts a calibration procedure. The potentiometer will be driven to the extreme points to calibrate the potentiometer.

The calibration is saved in flash, it does not have to be called on every start up.

The Motorized Linear Poti Bricklet is already factory-calibrated during testing at Tinkerforge.

BrickletMotorizedLinearPoti#get_api_version → [int, int, int]

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

BrickletMotorizedLinearPoti#get_response_expected(function_id) → bool
Parameters:function_id -- int

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

See #set_response_expected for the list of function ID constants available for this function.

BrickletMotorizedLinearPoti#set_response_expected(function_id, response_expected) → nil
Parameters:
  • function_id -- int
  • response_expected -- 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.

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

The following function ID constants are available for this function:

  • BrickletMotorizedLinearPoti::FUNCTION_SET_POSITION_CALLBACK_CONFIGURATION = 2
  • BrickletMotorizedLinearPoti::FUNCTION_SET_MOTOR_POSITION = 5
  • BrickletMotorizedLinearPoti::FUNCTION_CALIBRATE = 7
  • BrickletMotorizedLinearPoti::FUNCTION_SET_POSITION_REACHED_CALLBACK_CONFIGURATION = 8
  • BrickletMotorizedLinearPoti::FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletMotorizedLinearPoti::FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletMotorizedLinearPoti::FUNCTION_RESET = 243
  • BrickletMotorizedLinearPoti::FUNCTION_WRITE_UID = 248
BrickletMotorizedLinearPoti#set_response_expected_all(response_expected) → nil
Parameters:response_expected -- bool

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

BrickletMotorizedLinearPoti#get_spitfp_error_count → [int, int, int, int]

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 Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

The returned array has the values error_count_ack_checksum, error_count_message_checksum, error_count_frame and error_count_overflow.

BrickletMotorizedLinearPoti#set_bootloader_mode(mode) → int
Parameters:mode -- int

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

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

The following constants are available for this function:

  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletMotorizedLinearPoti::BOOTLOADER_STATUS_OK = 0
  • BrickletMotorizedLinearPoti::BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletMotorizedLinearPoti::BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletMotorizedLinearPoti::BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletMotorizedLinearPoti::BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletMotorizedLinearPoti::BOOTLOADER_STATUS_CRC_MISMATCH = 5
BrickletMotorizedLinearPoti#get_bootloader_mode → int

Returns the current bootloader mode, see #set_bootloader_mode.

The following constants are available for this function:

  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletMotorizedLinearPoti::BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
BrickletMotorizedLinearPoti#set_write_firmware_pointer(pointer) → nil
Parameters:pointer -- int

Sets the firmware pointer for #write_firmware. The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

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

BrickletMotorizedLinearPoti#write_firmware(data) → int
Parameters:data -- [int, int, ..61x.., int]

Writes 64 Bytes of firmware at the position as written by #set_write_firmware_pointer before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

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

BrickletMotorizedLinearPoti#set_status_led_config(config) → nil
Parameters:config -- int

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

  • BrickletMotorizedLinearPoti::STATUS_LED_CONFIG_OFF = 0
  • BrickletMotorizedLinearPoti::STATUS_LED_CONFIG_ON = 1
  • BrickletMotorizedLinearPoti::STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletMotorizedLinearPoti::STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletMotorizedLinearPoti#get_status_led_config → int

Returns the configuration as set by #set_status_led_config

The following constants are available for this function:

  • BrickletMotorizedLinearPoti::STATUS_LED_CONFIG_OFF = 0
  • BrickletMotorizedLinearPoti::STATUS_LED_CONFIG_ON = 1
  • BrickletMotorizedLinearPoti::STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletMotorizedLinearPoti::STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletMotorizedLinearPoti#get_chip_temperature → int

Returns the temperature in °C 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 bad accuracy. Practically it is only useful as an indicator for temperature changes.

BrickletMotorizedLinearPoti#reset → nil

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

BrickletMotorizedLinearPoti#write_uid(uid) → nil
Parameters:uid -- int

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

BrickletMotorizedLinearPoti#read_uid → int

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

BrickletMotorizedLinearPoti#get_identity → [str, str, str, [int, int, int], [int, int, int], int]

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

The position can be 'a', 'b', 'c' or 'd'.

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

The returned array has the values uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

BrickletMotorizedLinearPoti#register_callback(callback_id) { |param [, ...]| block } → nil
Parameters:callback_id -- int

Registers the given block with the given callback_id.

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

BrickletMotorizedLinearPoti#set_position_callback_configuration(period, value_has_to_change, option, min, max) → nil
Parameters:
  • period -- int
  • value_has_to_change -- bool
  • option -- str
  • min -- int
  • max -- int

The period in ms is the period with which the ::CALLBACK_POSITION callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the ::CALLBACK_POSITION callback.

The following options are possible:

Option Description
'x' Threshold is turned off
'o' Threshold is triggered when the value is outside the min and max values
'i' Threshold is triggered when the value is inside or equal to the min and max values
'<' Threshold is triggered when the value is smaller than the min value (max is ignored)
'>' Threshold is triggered when the value is greater than the min value (max is ignored)

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The default value is (0, false, 'x', 0, 0).

The following constants are available for this function:

  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_OFF = 'x'
  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_GREATER = '>'
BrickletMotorizedLinearPoti#get_position_callback_configuration → [int, bool, str, int, int]

Returns the callback configuration as set by #set_position_callback_configuration.

The following constants are available for this function:

  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_OFF = 'x'
  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_SMALLER = '<'
  • BrickletMotorizedLinearPoti::THRESHOLD_OPTION_GREATER = '>'

The returned array has the values period, value_has_to_change, option, min and max.

BrickletMotorizedLinearPoti#set_position_reached_callback_configuration(enabled) → nil
Parameters:enabled -- bool

Enables/Disables ::CALLBACK_POSITION_REACHED callback.

By default the callback is enabled.

BrickletMotorizedLinearPoti#get_position_reached_callback_configuration → bool

Returns the ::CALLBACK_POSITION_REACHED callback configuration as set by #set_position_reached_callback_configuration.

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:

motorized_linear_poti.register_callback BrickletMotorizedLinearPoti::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.

BrickletMotorizedLinearPoti::CALLBACK_POSITION
Parameters:position -- int

This callback is triggered periodically according to the configuration set by #set_position_callback_configuration.

The parameter is the same as #get_position.

BrickletMotorizedLinearPoti::CALLBACK_POSITION_REACHED
Parameters:position -- int

This callback is triggered if a new position as set by #set_motor_position is reached.

The parameter is the current position.

Constants

BrickletMotorizedLinearPoti::DEVICE_IDENTIFIER

This constant is used to identify a Motorized Linear Poti Bricklet.

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

BrickletMotorizedLinearPoti::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Motorized Linear Poti Bricklet.