The D1 mini is a mini wifi board based on ESP-8266EX. WeMos is the smallest version of the all-in-one development board for the super popular WiFi IoT chip, the ESP8266. While this board is fully compatible with the nodemcu firmware, it does not come pre-flashed with it. Since we don't open the original packaging, we don't get a chance to re-flash it before sending it to you. You must reflash it (using the NodeMCU flasher or the Arduino IDE) before you can use it. Also, three different berg-sticks are included. please note that these berg-sticks are not soldered.
11 digital input/output pins, all pins have interrupt/pwm/I2C/one-wire supported(except D0).
1 analog input(3.2V max input).
a Micro USB connection.
Compatible with Arduino.
Compatible with NodeMCU.
lots of shields.
Microcontroller - ESP-12F ;
Operating Voltage - 3.3v ;
Digital I/O - 11 ;
Analog Input Pins - 1 (max input: 3.2V) ;
Clock Speed - 80MHz/160MHz;
Flash - 4M Bytes ;
Dimensions (Length x Breadth) - 34.2mm x 25.6mm ;
Weight - 10g.