There’s QR code library for Arduino released 3 years ago. https://github.com/ricmoo/qrcode/ Well made library, works with less memory of Arduino while supporting QR code versions and error correction levels. You can easily create QR code data with above library and show code to OLED display with u8glib library. Below is sample sketch for showing QR code with “https://programresource.net” text data to OLED display, with inverted B/W on left / right half of screen. Very short and simple sketch which does amazing work.
There are many 128×64 or 128×32 monochrome OLED display out, and recently, I’ve seen tiny 64×32 dot OLED display sold. However, library such as Adafruit SSD1306 does not support this resolution at this time. Either find library which support tiny display, or make modification to library. I’ve modifed Adafruit SSD1306 library (version 2.2.0) to use with 64×32 OLED display. Modifications are 2 part in Adafruit_SSD1306.cpp file. Around line 549 and 888, add / modify for 64×32 resolution. Since I simply replaced code near line 888, this library won’t be compatible with other resolution. Simple Hello World sample sketch. Below includes sample sketch with modified library. Also, I’ve modified ESP_Adafruit_SSD1306 library …
I2C connection Monochrome OLED display is very handy to use. Easy wiring and various libraries provided, such as Adafruit GFX, u8glib, u8g2lib. Monochrome bitmap can also be displayed. You need to prepare bitmap image and convert to hex data. There are tools you can download, but I couldn’t find one that is easy to use. So, I’ve created easy-to-use tool to convert bmp file to hex data (for Windows). Built with Visual Studio / C++. Use freely, no support, use at your own risk. Simply create bitmap file with MS paintbrush for example, save as 24bit bmp file. Launch tool, drag and drop bmp file to tool. You get hex …