: Features 16 digital GPIO pins (11 usable) and 1 10-bit analog input (ADC) pin. Power Requirements ESP8266 WiFi Module for Dummies - Instructables
: Supports UART, SPI, I2C, and I2S communications. ESP8266 NodeMCU WiFi Module User Manual
: 2.4GHz Wi-Fi (802.11 b/g/n) with an integrated PCB antenna. : Features 16 digital GPIO pins (11 usable)
: Tensilica Xtensa 32-bit LX106 RISC running at 80MHz to 160MHz. Memory : Typically 4MB Flash and 64KB to 128KB RAM. ESP8266 NodeMCU WiFi Module User Manual
The is an open-source development board that integrates the ESP8266 Wi-Fi system-on-chip (SoC) with a user-friendly USB interface, making it a popular choice for Internet of Things (IoT) projects. It allows for standalone operation or can be used to add Wi-Fi to existing microcontroller systems. Technical Specifications