In this tutorial we focus only on GPIO pins of ESP8266 and How to use efficiently ?
ESP8266 comes in many variants most popular is ESP-12 and ESP-01. Use of ESP8266 as just a Serial-to-WiFi bridge with arduino is most common mistake newbies do. ESP8266 itself is very powerful microcontroller. Lets compare with Arduino with ESP8266. To get serial and IOs expantion like Arduino you can use NodeMCU. Difference between ESP12, ESP01 and NodeMCU is only of Flash memory and Number of IOs are available to user. Programming and functioning of all three devices is same.
Continue reading ESP8266 arduino digital IO