LOLIN(WEMOS) D1 R2 & mini

Compact and full-size ESP8266 dev boards - perfect for IoT projects using Arduino-style pins.

Micro-USB
LOLIN(WEMOS) D1 R2 & mini board
34.2 × 25.6 mm
ESP8266
MCU
160MHz
clock
4MB
flash
~80KB
SRAM
17· 1 ADC
GPIO
Wi-Fi
radio
On this page

Pinout

View:
LOLIN(WEMOS) D1 R2 & mini pinout diagram
Pinout notes The pinout diagram for this ESP32-based module highlights its versatility and ease of use for IoT and embedded projects. The module includes a RST pin for…

The pinout diagram for this ESP32-based module highlights its versatility and ease of use for IoT and embedded projects. The module includes a RST pin for resetting the board, which is crucial for debugging and testing. On the power side, the board provides a 3.3V output pin and VBUS for powering external components, along with multiple GND pins to ensure proper grounding.

This pinout features a range of GPIO pins, such as GPIO16, GPIO14, GPIO15, and GPIO4, all of which are multi-functional and can be used for both digital I/O and peripheral interfacing. Communication protocols are well-supported, with dedicated pins for SPI, including SCK (GPIO14), MISO (GPIO12), and MOSI (GPIO13). These pins enable high-speed communication with external devices like sensors, displays, and storage modules.

For I2C communication, the board uses GPIO5 for SCL and GPIO4 for SDA, making it easy to connect to peripherals like temperature sensors, accelerometers, or OLED displays. A built-in LED is connected to GPIO2, allowing developers to use it for visual feedback or debugging during project development.

Getting started

flash your first firmware in ~2 minutes
Tool:
1
Connect over USB
Serial chip: CH340. Not detected? Hold BOOT while plugging in.
2
Flash with your tool
Arduino IDE, PlatformIO, ESPHome or esptool - copy the settings on the right.
3
Verify it runs
The blink example uses GPIO8 - swap for your board's LED pin if different.
Tools → Board settings Copy
Board:            Esp8266 Wemos D1mini
Flash Size:       4 MB · DIO
Upload Speed:     921600

// blink
pinMode(8, OUTPUT);
digitalWrite(8, LOW);   // on (often inverted)
platformio.ini Copy
[env:d1_mini]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600
device.yaml Copy
esp32:
  board: esp32dev
  variant: d1_mini
  framework:
    type: esp-idf

# blink - GPIO8
output:
  - platform: gpio
    pin: 8
    id: led_out
light:
  - platform: binary
    name: "LED"
    output: led_out
shell Copy
esptool.py --chip esp8266 --port /dev/ttyACM0 \
  write_flash 0x0 firmware.bin

Specifications

ESP8266 · 34.2 × 25.6 mm
Compute
MCU
ESP8266
Clock
160 MHz
SRAM · Flash
~80 KB · 4 MB
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
-
Antenna
PCB
I/O
GPIO · ADC
17 · 1
UART · I²C · SPI
2 · 1 · 2
PWM
-
Power
USB
Micro-USB
Serial
CH340
Boot address
0x0000
Flashing
Upload · OTA
esptool · esp_ota
Flash · Boot mode
DIO · -
Sketch · Data
- · 80 KB
25.6 mm34.2 mm
34.2 × 25.6 mm · pin pitch 2.54 mm
The LOLIN(WEMOS) D1 R2 & mini uses esptool for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO.

About this board

At $5.00 it's cheaper than most ESP8266 boards, which usually run around $15.


The LOLIN(WEMOS) D1 mini (also written as WeMos D1 mini, LOLIN D1 mini, or D1 Mini) is a compact ESP8266 development board built around Espressif's ESP-8266EX chip, a CH340 USB-to-serial converter, and 4 MB of flash. Measuring just 34.2 x 25.6 mm, it offers 11 digital IO pins, 1 analog input, and a wide "mini shield" ecosystem for easy expansion. It's popular for Wi-Fi IoT projects, sensor nodes, and home automation. In this guide, you'll find the WeMos D1 mini pinout, datasheet, technical specs, and setup instructions.

Resources

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