Ruby - OLED 128x64 Bricklet

This is the description of the Ruby API bindings for the OLED 128x64 Bricklet. General information and technical specifications for the OLED 128x64 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).

Hello World

Download (example_hello_world.rb)

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

require 'tinkerforge/ip_connection'
require 'tinkerforge/bricklet_oled_128x64'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XYZ' # Change XYZ to the UID of your OLED 128x64 Bricklet

ipcon = IPConnection.new # Create IP connection
oled = BrickletOLED128x64.new UID, ipcon # Create device object

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

# Clear display
oled.clear_display

# Write "Hello World" starting from upper left corner of the screen
oled.write_line 0, 0, 'Hello World'

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

Pixel Matrix

Download (example_pixel_matrix.rb)

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

require 'tinkerforge/ip_connection'
require 'tinkerforge/bricklet_oled_128x64'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XYZ' # Change XYZ to the UID of your OLED 128x64 Bricklet
WIDTH = 128 # Columns (each 1 pixel wide)
HEIGHT = 8 # Rows (each 8 pixels high)

def draw_matrix(oled, start_column, start_row, column_count, row_count, pixels)
  pages = []

  # Convert pixel matrix into 8bit pages
  for row in 0..row_count - 1
    pages[row] = []

    for column in 0..column_count - 1
      pages[row][column] = 0

      for bit in 0..7
        if pixels[row * 8 + bit][column]
          pages[row][column] |= 1 << bit
        end
      end
    end
  end

  # Merge page matrix into single page array
  data = []

  for row in 0..row_count - 1
    for column in 0..column_count - 1
      data.push pages[row][column]
    end
  end

  # Set new window
  oled.new_window start_column, start_column + column_count - 1, \
                  start_row, start_row + row_count - 1

  # Write page data in 64 byte blocks
  for i in (0..data.length - 1).step(64)
    block = data[i, 64]
    oled.write block.fill(0, block.length, 64 - block.length)
  end
end

ipcon = IPConnection.new # Create IP connection
oled = BrickletOLED128x64.new UID, ipcon # Create device object

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

# Clear display
oled.clear_display

# Draw checkerboard pattern
pixels = []

for row in 0..HEIGHT * 8 - 1
  pixels[row] = []

  for column in 0..WIDTH - 1
    pixels[row][column] = (row / 8) % 2 == (column / 8) % 2
  end
end

draw_matrix oled, 0, 0, WIDTH, HEIGHT, pixels

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

Scribble

Download (example_scribble.rb)

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

require 'rgd'
require 'tinkerforge/ip_connection'
require 'tinkerforge/bricklet_oled_128x64'

include Tinkerforge

HOST = 'localhost'
PORT = 4223
UID = 'XYZ' # Change to your UID
WIDTH = 128 # Columns (each 1 pixel wide)
HEIGHT = 8 # Rows (each 8 pixels high)

def draw_image(oled, start_column, start_row, column_count, row_count, image)
  pages = []

  # Convert image pixels into 8bit pages
  for row in 0..row_count - 1
    pages[row] = []

    for column in 0..column_count - 1
      pages[row][column] = 0

      for bit in 0..7
        index = image[column, (row * 8) + bit]
        rgba = image.rgba index

        if rgba[0] > 0
          pages[row][column] |= 1 << bit
        end
      end
    end
  end

  # Merge page matrix into single page array
  data = []

  for row in 0..row_count - 1
    for column in 0..column_count - 1
      data.push pages[row][column]
    end
  end

  # Set new window
  oled.new_window start_column, start_column + column_count - 1, \
                  start_row, start_row + row_count - 1

  # Write page data in 64 byte blocks
  for i in (0..data.length - 1).step(64)
    block = data[i, 64]
    oled.write block.fill(0, block.length, 64 - block.length)
  end
end

ipcon = IPConnection.new # Create IP connection
oled = BrickletOLED128x64.new UID, ipcon # Create device object

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

# Clear display
oled.clear_display

# Draw checkerboard pattern
image = RGD::Image.create WIDTH, HEIGHT * 8
black = image.color_allocate 0, 0, 0
white = image.color_allocate 255, 255, 255
origin_x = WIDTH / 2
origin_y = HEIGHT * 8 / 2
length = HEIGHT * 8 / 2 - 2
angle = 0

puts 'Press key to exit'

Thread.new do
  $stdin.gets
  exit
end

while true
    radians = Math::PI * angle / 180.0
    x = (origin_x + length * Math.cos(radians)).to_i
    y = (origin_y + length * Math.sin(radians)).to_i

    image.filled_rectangle 0, 0, WIDTH, HEIGHT * 8, black
    image.line origin_x, origin_y, x, y, white

    draw_image oled, 0, 0, WIDTH, HEIGHT, image
    sleep 0.025

    angle += 1
end

API

All methods listed below are thread-safe.

Basic Functions

BrickletOLED128x64::new(uid, ipcon) → oled_128x64
Parameters:
  • uid -- str
  • ipcon -- IPConnection

Creates an object with the unique device ID uid:

oled_128x64 = BrickletOLED128x64.new 'YOUR_DEVICE_UID', ipcon

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

BrickletOLED128x64#write(data) → nil
Parameters:data -- [int, int, ..61x.., int]

Appends 64 byte of data to the window as set by #new_window.

Each row has a height of 8 pixels which corresponds to one byte of data.

Example: if you call #new_window with column from 0 to 127 and row from 0 to 7 (the whole display) each call of #write (red arrow) will write half of a row.

Display pixel order

The LSB (D0) of each data byte is at the top and the MSB (D7) is at the bottom of the row.

The next call of #write will write the second half of the row and the next two the second row and so on. To fill the whole display you need to call #write 16 times.

BrickletOLED128x64#new_window(column_from, column_to, row_from, row_to) → nil
Parameters:
  • column_from -- int
  • column_to -- int
  • row_from -- int
  • row_to -- int

Sets the window in which you can write with #write. One row has a height of 8 pixels.

The columns have a range of 0 to 127 and the rows have a range of 0 to 7.

BrickletOLED128x64#clear_display → nil

Clears the current content of the window as set by #new_window.

BrickletOLED128x64#write_line(line, position, text) → nil
Parameters:
  • line -- int
  • position -- int
  • text -- str

Writes text to a specific line (0 to 7) with a specific position (0 to 25). The text can have a maximum of 26 characters.

For example: (1, 10, "Hello") will write Hello in the middle of the second line of the display.

You can draw to the display with #write and then add text to it afterwards.

The display uses a special 5x7 pixel charset. You can view the characters of the charset in Brick Viewer.

Advanced Functions

BrickletOLED128x64#set_display_configuration(contrast, invert) → nil
Parameters:
  • contrast -- int
  • invert -- bool

Sets the configuration of the display.

You can set a contrast value from 0 to 255 and you can invert the color (black/white) of the display.

The default values are contrast 143 and inverting off.

BrickletOLED128x64#get_display_configuration → [int, bool]

Returns the configuration as set by #set_display_configuration.

The returned array has the values contrast and invert.

BrickletOLED128x64#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.

BrickletOLED128x64#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.

BrickletOLED128x64#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:

  • BrickletOLED128x64::FUNCTION_WRITE = 1
  • BrickletOLED128x64::FUNCTION_NEW_WINDOW = 2
  • BrickletOLED128x64::FUNCTION_CLEAR_DISPLAY = 3
  • BrickletOLED128x64::FUNCTION_SET_DISPLAY_CONFIGURATION = 4
  • BrickletOLED128x64::FUNCTION_WRITE_LINE = 6
BrickletOLED128x64#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.

BrickletOLED128x64#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.

Constants

BrickletOLED128x64::DEVICE_IDENTIFIER

This constant is used to identify a OLED 128x64 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.

BrickletOLED128x64::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a OLED 128x64 Bricklet.