The NodeMcu is an open-source board with inbuilt ESP-12E WIFI module. This is not a weakling like the Arduino's, with 512kb of memory and a processor at 40Mhz there is not a shortage of sources. This sign is extremely suitable for starting IoT (Internet of Things) applications. Programming the NodeMcu is slightly different than normal, with the API similar to NodeJS, this module receives the commands through the LUA scripts being uploaded.

This concerns version 3 of the NodeMCU series, which is somewhat wider than the previous version and therefore no longer fits neatly on a breadboard. To make this right, an I / O shield has been designed to fit this NodeMCU perfectly. This version contains the CH340G version to save costs instead of the CP2102 serial chip.

Properties
Wireless 802.11 b / g / n standard
Supports STA / AP / STA + AP
Standard on 9600 baud

Built-in TCP / IP protocol stack to support multiple TCP Client connections (5 MAX)
D0 ~ D8, SD1 ~ SD3: used as GPIO, PWM, IIC, etc., port driver capability 15mA
AD0: 1 channel ADC
Power input: 4.5V ~ 9V (10VMAX), USB powered
Current: continuous transmission: ≈70mA (200mA MAX), Standby: <200uA
Transfer rate: 110-460800bps
Support UART / GPIO data communication interface
Remote firmware upgrade (OTA)
Support Smart Link Smart Networking