The NodeMcu is an open source card with an integrated WIFI ESP-12E module. It is not a weak like the Arduino, with 512 KB of memory and a processor at 40Mhz there is no shortage of sources. This sign is extremely suitable for starting IoT (Internet of Things) applications. The programming of NodeMcu is slightly different from normal, with the API which resembles NodeJS, this module receives commands via the LUA scripts being downloaded.
This concerns version 2 of the NodeMCU series, thinner than the previous version and therefore better suited to a breadboard. Now there is a row on both sides of the board when you place it in the middle of a bread board. This saves a lot by connecting I / O.
Integrated 2102 series chip drivers can be found here
802.11 b / g / n wireless standard
STA / AP / STA + AP support
Standard on 9600 baud
Integrated TCP / IP protocol stack to support multiple TCP client connections (5 MAX)
D0 ~ D8, SD1 ~ SD3: used as GPIO, PWM, IIC, etc., port driver capacity 15mA
AD0: 1 ADC channel
Power input: 4.5 V ~ 9 V (10 VMAX), powered by USB
Current: continuous transmission: ≈70mA (200mA MAX), standby: