The D1 R2 is a WiFi capable ESP8266EX based development board in the form of the common Arduino UNO board format. This board is compatible with the Arduino IDE and with NodeMCU. The D1 R2 also features an on-board switching power supply which allows you to power the board from a power supply up to 12V.
SPECIFICATION:
Microcontroller: ESP8266EX
Operating Voltage: 3.3V
Digital I/O Pins: 11 (all I/O pins have interrupt/pwm/I2C/one-wire capability, except for D0)
Analog Input Pins: 1 (3.2V max input)
Flash Memory: 4MB
On-Board Switching Power Supply
Input Voltage Range: 9V to 12V
Output: 5V at 1A Max
Board Dimensions: 68.6mm x 53.4mm (2.701" x 2.102") / Long x Wide
Weight: 21.8g (0.769oz)