FHEM: Home Automation remote display using small OLED and MQTT
I wanted to have a small display with some essential Home Automation data. So I buy an 1.3″ OLED display with I2C interface and started to look for some existing code for an ESP8266. The display should be feed using WiFi and be portable, so I can place it where needed.
I started with ESPeasy, as there is already support for multiple pages with text lines. Unfortunately the code is written to show sensor data of directly connected sensor only. No option to publish free text or data from a Home Automation system. The ESPeasy code will save the text to flash memory on every change when using the Web GUI. The flash memory would wear out after some month with my use case.
Finally I decided to start my own code. First I had to find out that the OLED display is not an SD1306 but a SH1106 one. Although some people state that these are more or less the same, the SD1306 libraries did not work for me. Then I found https://github.com/ThingPulse/esp8266-oled-ssd1306 which works well for me.
Starting with SSD1306UiDemo.ino I added WiFi and MQTT libaries and code.
My code will show 6 lines of text on two frames (3 lines each). The frames will change every 5 seconds. The content of the text lines is published by a FHEM server. As there was no easy way to integrate the display using a MQTT_DEVICE definition in FHEM, I wrote my own perl mqttmsg sub function and used the FHEM notify definition to publish changes to the display.
a small video
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