Microcontroller projects
OLED Monitor showing MQTT data
last updated: 2022-09-09
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Intro
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:
https://www.weigu.lu/microcontroller/ardlib_SSD1322_I2C/index.html
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.
I used the parallel to I2C board from the GTK281 PCB with the following changes:
- No 5V! Connect 5V Pin of Header with 3V
- Connect display pin 19 with display pin 20 (both 3V: 6800 // mode)
- Move Reset from display pin Pin 17 to 16
- Gnd to display pin 17
- BL to display pin 18
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.
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....
Housing
The housing is drawn in FreeCAD. The stl files are on github.
Downloads
- Everything on github: https://github.com/weigu1/mqtt_oled_mon
