Wemos D1 Mini is a compact and powerful Wi-Fi-enabled microcontroller board based on the ESP8266 chip. Designed for IoT (Internet of Things) projects, it combines the functionality of a full ESP8266 module with a small, breadboard-friendly form factor.
Microcontroller: ESP8266EX
Flash Memory: 4MB
Operating Voltage: 3.3V (inputs NOT 5V-tolerant)
I/O: 11 digital IO (all support PWM, I2C, and interrupts), 1 analog input (0–3.2V)