Software part for my engineering thesis project: "Door message board for displaying information defined by the remote user". This part handles the e-ink screen using ESP32 microcontroller, handles MQTT requests. Written using ESP-IDF framework
When MCU is neither receiving data nor changing displaying text, it should be in sleep mode. It should wake up after user-defined time, to check whether new message has been published. This would save energy. Decision whether to use light sleep, or deep sleep should be made. Choosing deep sleep mode will require changing Wi-Fi connection handling.
Currently changing broker require changing hard-coded data: IPv4 address, MQTT credentials and sometimes wi-fi credentials. This could be resolved, by turning on wireless hotspot in ESP32. It would allow user to connect to hotspot, set required data using MQTT client app, next the device should use stored data to connect with a broker. Similar functionalities are used in e.g. printers.