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device GUI / October, 2022


The previous OLED display was really cute for its small 128x32px size, but it wasn’t working well for the QR code.

Imagine a square with less than 10x10mm, shinning bright (OLED). It was really hard to focus with the smartphone camera.

I’ve then decided to switch for a similar but bigger I2C OLED display, now with 128x64px:

_DSC9705

Then I’ve took advantage of its taller real state to improve and/or implement new screens:

  • splash: more about that soon, with an nerdy extra feature;
  • wi-fi reset;
  • wi-fi setup: cold start or after reset;
  • E-TKT ready state: QR code + text of the local assigned IP to access the web app;
  • printing progress;
  • printing finished;
  • cutting, feeding and reeling: requested manually from the web app);
  • saving settings: more about that in the following updates;
  • rebooting;

It turns out that having not so many pixels to push around is pretty funny. Also, I’ve used symbols with a dedicated font to improve the meaning and communication.

Thanks to olikraus for the amazing U8g2 library that is super useful.