Microcontroller projects

OLED Monitor showing MQTT data

last updated: 2022-09-09

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I had some spare monochrome OLED displays from an old project. OLED display are are getting cheaper. They need less power, are brighter and have a greater temperature range then LCDs. And you can never have enough monitors :).

The displays are used to show MQTT data from my new Energy Storage System (ESS) from Victron (3 phase 24 kVA). More infos soon on http://www.prosumer.lu.


OLED display NHD-2.7-12864WDW3

The displays are 128x64 monochrome display from Newhaven with 2.7' screen. They can by found at .

The display can be used in parallel mode or over SPI. As I needed I2C for 4 displays, I'm using my modified PCBs from the old project. More infos on this page:


On one display (OLED3) the first lines are not working, so I don't use this lines :).

I2C Boards

The board was designed in Kicad. The schematic is already changed, but the PCB has still to be modified in Kicad.

SSD1322 I2C circuit

I used the parallel to I2C board from the GTK281 PCB with the following changes:

SSD I2C boardSSD I2C board back

As I needed 4 different I2C addresses, I had to modify the pin connections A0-A2 (all connected to GND) for 3 boards. So I got the addresses 0x20, 0x21, 0x22 and 0x23.

SSD1322 I2C PCB2


Arduino library

To install the library download SSD1322_I2C.zip, from the git page and click in Arduino IDE Sketch > Include Library > Add .ZIP Library....


The housing is drawn in FreeCAD. The stl files are on github.