Wemos D1 is a WIFI development board based on ESP8266 12E,The functioning is similar to that NodeMcu,except that the hardware is built resembling arduino UNO
Microcontroller ESP-8266EX Operating Voltage 3.3V Digital I/O Pins 11 Analog Input Pins 1 Clock Speed 80MHz/160MHz FLash 4M bytes Length 68.6mm Width 53.4mm Pin Function ESP-8266 Pin TX TXD TXD RX RXD RXD A0 Analog input, max 3.3V input A0 D0 IO GPIO16 D1.