Ethernet Port

[ttoopp]

Hi, is it possible, to use an ESP with Ethernet port?

[deklaus]

Short answer: Probably not without modification.

Longer answer: The ESP should be pin-compatible, but can also be connected via wires. In addition to the power supply (5 V in and 3.3 V out), a serial interface to the PIC, I2C to the OLED, and optionally to a DS18B20 are required (see circuit diagrams).
The ESP is primarily responsible for the web UI and the OLED and connects to the WiFi in setup.ino (see ‘Setup WIFI’). This process is repeated in reconnect() if the connection is lost as an MQTT client (“if (!MQTTclient.connected()”).
With an Ethernet port this process may be unnecessary and with these few adjustments or by commenting out the lines, it might work, but I haven't tested it.

If you want to try it out, I would appreciate your feedback.