NodeMCU started on 13 Oct 2014
- Hong committed the first file of nodemcu-firmware to GitHub.
- Huang R committed the gerber file of an ESP8266 board
- Tuan PM ported MQTT client library from Contiki to the ESP8266 SoC platform
- Devsaurus ported the u8glib to the NodeMCU

What is I2C
The Inter-Integrated Circuit bus (IIC or I2C bus) is a synchronous, multi-master/multi-slave, packet switched serial data bus. It is widely used for low-speed communications in digital systems on board and off board.

https://www.realdigital.org/doc/6da47099f4ada78618d85b3d68613ac8