Display values on an I2C screen via ESP8266

Prerequisites

To build this setup, you will need:

• 1 ESP8266;
• 1 I2C 128×64 OLED screen;
• 1 LF33CV regulator (5v to 3.3v);
• 1 1kΩ resistor (pull-up);
• 2 4.7kΩ resistors.

Warning!
The code is in LUA and therefore requires the ESP8266 to have the nodemcu firmware.

Wiring

Code

Github

Principle

The principle is as follows:

1. The ESP creates an MQTT client with a unique id;
2. It connects to the MQTT broker;
3. The client subscribes to a specific topic where the desired data is published;
4. The ESP displays the data on the screen for the first time;
5. Then each time the MQTT broker receives new data on this topic, our client updates the data on the screen.

Result