ESp8266 ESP-12-E
The ESP-12E has a ESP8266 core processor, with a module of 4MB of flash memory. Also it has 22 pins and a on board printed antenna. It also has a built-in LED which is directly connected to the UART TX line. You can use the TX pin as GPIO1 to control the LED, but only if you don't use UART.
References
| Reference | URL |
|---|---|
| ESP-12E | https://github.com/lvidarte/esp8266/wiki/ESP%E2%80%9012E |
ESP8266 Thing Development Board Hookup Guide | https://learn.sparkfun.com/tutorials/esp8266-thing-development-board-hookup-guide/all |