oled-control

Ruby Gem for SSD1311 based 20x4 OLED display from wide.hk. Should theoretically work for 20x2 and 16x2 as well, with some modifications.

Usage

Add to your Gemfile: gem 'oled-control', and bundle install

Example code

require 'oled-control/oled'

oled = OLED.new
oled.clear # clear display
oled.set_cursor(0, 0) # set cursor position to column 0, row 0
oled.write('Hello, world!')

Should you be so unlucky as to mount the display upside-down, do not despair! Just oled.flip to turn things around again.

Configure I2C bus and address

The library defaults to I2C-bus /dev/i2c-1 and I2C device address 0x3C If you require another bus/address, you can use

OLED.new('/dev/i2c-2', 0x45)

Character set

To utilize the various supported characters (I use the ROM A set on the SSD1311), the library will first do a conversion to ISO-8859-1, and then do character replacement to make the characters match up.

See the @character_conversion variable in this file and the SSD1311 datasheet for reference.

Custom characters

It is possible to create eight custom characters numbered from 0 to 7. Example:

oled.create_character(0, [0b11000,
                          0b11100,
                          0b11110,
                          0b11111,
                          0b11110,
                          0b11100,
                          0b11000,
                          0b00000])
                             
oled.write("My custom char: \x00")

Testing without ruby

Checkout the repository git clone https://github.com/sokkalf/oled-control.git

Make a build directory, cd build, and cmake .. Makefiles should be generated.

You can now run make to build the test program, and ./oled_control to run it.

It will play back a bit of text from Zero Wing