GitHub

In this repository you can learn how to connect a ESP8266 WiFi module (ESP-01) to an Arduino UNO connected via Serial (Tx Rx) and send data to a MySQL database in a webhosting

Then I notice it was too dificult and use a nodeMCU connected via serial to an Arduino that sends 4 numbers comma separated. The program for the Arduino that sends data is called Sender The program ...
GitHub

nro-bot/robot_esp8266-12E

ESP8266 SMT Module - ESP-12E, however you don't want to work directly with the SMT, but instead with the: NodeMCU = open-source firmware, may also refer to their very popular devkit board design which ...
Hackaday

esp-12f

While the ESP32 is clearly a superior piece of hardware, we think you’ll agree that the ESP8266 is just too useful not to have a dozen or so kicking around the parts bin at any given time. Cheap, easy ...