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# Ruby - LED Strip Bricklet

This is the description of the Ruby API bindings for the LED Strip Bricklet. General information and technical specifications for the LED Strip 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_led_strip'

    include Tinkerforge

    HOST = 'localhost'
    PORT = 4223
    UID = 'abc' # Change to your UID

    ipcon = IPConnection.new # Create IP connection
    led_strip = BrickletLEDStrip.new UID, ipcon # Create device object

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

    # Set first 10 LEDs to green
    r = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
    g = [255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0]
    b = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ,0 ,0]
    led_strip.set_rgb_values 0, 10, r, g, b

    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_led_strip'

    include Tinkerforge

    HOST = 'localhost'
    PORT = 4223
    UID = 'abc' # Change to your UID

    NUM_LEDS = 16

    r = [0]*NUM_LEDS
    g = [0]*NUM_LEDS
    b = [0]*NUM_LEDS
    r_index = 0

    ipcon = IPConnection.new # Create IP connection
    led_strip = BrickletLEDStrip.new UID, ipcon # Create device object

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

    # Set frame duration to 50ms (20 frames per second)
    led_strip.set_frame_duration 50

    # Register frame rendered callback
    led_strip.register_callback(BrickletLEDStrip::CALLBACK_FRAME_RENDERED) do |length|
        b[r_index] = 0
        if(r_index == NUM_LEDS-1)
            r_index = 0
        else
            r_index += 1
        end

        b[r_index] = 255

        # Set new data for next render cycle
        led_strip.set_rgb_values 0, NUM_LEDS, r, g, b
    end

    # Set initial rgb values to get started
    led_strip.set_rgb_values(0, NUM_LEDS, r, g, b)

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

## API

All methods listed below are thread-safe.

### Basic Functions

`BrickletLEDStrip``::``new`(uid, ipcon) → led_strip

  Parameters:

  - uid -- str
  - ipcon -- IPConnection

  Creates an object with the unique device ID `uid`:

      led_strip = BrickletLEDStrip.new 'YOUR_DEVICE_UID', ipcon

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

`BrickletLEDStrip``#``set_rgb_values`(index, length, r, g, b) → nil

  Parameters:

  - index -- int
  - length -- int
  - r -- [int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int]
  - g -- [int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int]
  - b -- [int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int]

  Sets the rgb values for the LEDs with the given length starting from index.

  The maximum length is 16, the index goes from 0 to 319 and the rgb values have 8 bits each.

  Example: If you set

  - index to 5,
  - length to 3,
  - r to [255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
  - g to [0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] and
  - b to [0, 0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

  the LED with index 5 will be red, 6 will be green and 7 will be blue.

  Note

  Depending on the LED circuitry colors can be permuted.

  The colors will be transfered to actual LEDs when the next frame duration ends, see `#set_frame_duration`.

  Generic approach:

  - Set the frame duration to a value that represents the number of frames per second you want to achieve.
  - Set all of the LED colors for one frame.
  - Wait for the `::CALLBACK_FRAME_RENDERED` callback.
  - Set all of the LED colors for next frame.
  - Wait for the `::CALLBACK_FRAME_RENDERED` callback.
  - and so on.

  This approach ensures that you can change the LED colors with a fixed frame rate.

  The actual number of controllable LEDs depends on the number of free Bricklet ports. See here for more information. A call of `#set_rgb_values` with index + length above the bounds is ignored completely.

`BrickletLEDStrip``#``get_rgb_values`(index, length) → [[int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int], [int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int], [int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int]]

  Parameters:

  - index -- int
  - length -- int

  Returns the rgb with the given length starting from the given index.

  The values are the last values that were set by `#set_rgb_values`.

  The returned array has the values `r`, `g` and `b`.

`BrickletLEDStrip``#``set_frame_duration`(duration) → nil

  Parameters: | duration -- int

  Sets the frame duration in ms.

  Example: If you want to achieve 20 frames per second, you should set the frame duration to 50ms (50ms * 20 = 1 second).

  For an explanation of the general approach see `#set_rgb_values`.

  Default value: 100ms (10 frames per second).

`BrickletLEDStrip``#``get_frame_duration` → int

  Returns the frame duration as set by `#set_frame_duration`.

`BrickletLEDStrip``#``get_supply_voltage` → int

  Returns the current supply voltage of the LEDs. The voltage is given in mV.

`BrickletLEDStrip``#``set_clock_frequency`(frequency) → nil

  Parameters: | frequency -- int

  Sets the frequency of the clock in Hz. The range is 10000Hz (10kHz) up to 2000000Hz (2MHz).

  The Bricklet will choose the nearest achievable frequency, which may be off by a few Hz. You can get the exact frequency that is used by calling `#get_clock_frequency`.

  If you have problems with flickering LEDs, they may be bits flipping. You can fix this by either making the connection between the LEDs and the Bricklet shorter or by reducing the frequency.

  With a decreasing frequency your maximum frames per second will decrease too.

  The default value is 1.66MHz.

  Note

  The frequency in firmware version 2.0.0 is fixed at 2MHz.

  New in version 2.0.1 (Plugin).

`BrickletLEDStrip``#``get_clock_frequency` → int

  Returns the currently used clock frequency as set by `#set_clock_frequency`.

  New in version 2.0.1 (Plugin).

`BrickletLEDStrip``#``set_chip_type`(chip) → nil

  Parameters: | chip -- int

  Sets the type of the led driver chip. We currently support the chips

  - WS2801 (`chip` = 2801),
  - WS2811 (`chip` = 2811) and
  - WS2812 (`chip` = 2812).

  The WS2812 is sometimes also called "NeoPixel", a name coined by Adafruit.

  The default value is WS2801 (`chip` = 2801).

  The following constants are available for this function:

  - BrickletLEDStrip::CHIP_TYPE_WS2801 = 2801
  - BrickletLEDStrip::CHIP_TYPE_WS2811 = 2811
  - BrickletLEDStrip::CHIP_TYPE_WS2812 = 2812

  New in version 2.0.2 (Plugin).

`BrickletLEDStrip``#``get_chip_type` → int

  Returns the currently used chip type as set by `#set_chip_type`.

  The following constants are available for this function:

  - BrickletLEDStrip::CHIP_TYPE_WS2801 = 2801
  - BrickletLEDStrip::CHIP_TYPE_WS2811 = 2811
  - BrickletLEDStrip::CHIP_TYPE_WS2812 = 2812

  New in version 2.0.2 (Plugin).

### Advanced Functions

`BrickletLEDStrip``#``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.

`BrickletLEDStrip``#``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.

`BrickletLEDStrip``#``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 and callbacks it is always disabled.

  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:

  - BrickletLEDStrip::FUNCTION_SET_RGB_VALUES = 1
  - BrickletLEDStrip::FUNCTION_SET_FRAME_DURATION = 3
  - BrickletLEDStrip::FUNCTION_SET_CLOCK_FREQUENCY = 7
  - BrickletLEDStrip::FUNCTION_SET_CHIP_TYPE = 9

`BrickletLEDStrip``#``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.

`BrickletLEDStrip``#``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

`BrickletLEDStrip``#``register_callback`(id) { |param [, ...]| block } → nil

  Parameters: | id -- int

  Registers a callback with ID id to the given block. The available IDs with corresponding function signatures are listed below.

### 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:

    led_strip.register_callback BrickletLEDStrip::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.

`BrickletLEDStrip``::``CALLBACK_FRAME_RENDERED`

  Parameters: | length -- int

  This callback is triggered directly after a new frame is rendered.

  You should send the data for the next frame directly after this callback was triggered.

  For an explanation of the general approach see `#set_rgb_values`.

### Constants

`BrickletLEDStrip``::``DEVICE_IDENTIFIER`

  This constant is used to identify a LED Strip 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.

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