The world of Wemos D1 Mini Boards

The world of Wemos D1 Mini Boards

· 3 min read

Some readers recently asked me about the Wemos D1 mini usage in my projects and how this board can be used with ESPHome.

For most of my Arduino & ESPHome projects I use a Wemos D1 mini (v3.1.0) or Wemos D1 mini Pro (v1.1.0). The third board of the family is the is the D1 mini light. I never used one of the light versions, most of the time you can get the D1 mini & D1 mini pro for almost identical prices at alipexpress.com.

The boards are equipped with a ESP-8266EX chip running at 80 or 160MHz, like many other Node MCU boards. They provide [12 I/O pins - 11 digital and 1 analog input pin - enough for the most projects.

I also like the board because it is little smaller than a classic Node MCU board. The dimensions are 34.2 mm x 25.6mm. It is so small; it even fits into a small dollhouse Mini TV.

Wemos recently upgraded both boards. The Wemos D1 mini is now on version 4.0.0 and the Wemos D1 mini Pro on v2.0.0. Both boards got USB type C connectors instead of micro USB. The pro version also got a lithium battery interface charging interface and a LOLIN I2C Port. To fit everything on the board D1 mini Pro has grown a bit.

Pinout

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The pinouts of the D1 mini vs. D1 mini Pro are identical, also the D1 mini shares the same pin layout. And with with the latest board versions of the D1 mini (v4.0.0) vs. D1 mini Pro (v2.0.0) Wemos keeps the pin layout compatible.

D1 mini Pro Pinout

PinFunctionESP-8266 Pin
TXTXDTXD
RXRXDRXD
A0Analog input, max 3.2VA0
D0IOGPIO16
D1IO, SCLGPIO5
D2IO, SDAGPIO4
D3IO, 10k Pull-upGPIO0
D4IO, 10k Pull-up, BUILTIN_LEDGPIO2
D5IO, SCKGPIO14
D6IO, MISOGPIO12
D7IO, MOSIGPIO13
D8IO, 10k Pull-down, SSGPIO15
GGroundGND
5V5V
3V33.3V3.3V
RSTResetRST

Source pinout: https://www.wemos.cc

D1 mini vs. D1 mini Pro

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There are only minor differences between the D1 mini and the D1 mini Pro (V1.1.0) I have. For most projects it should not really matter which board you use. The pin out layout is the same.

The most obvious visible difference is the ceramic antenna and the external antenna connector on the board. With the ceramic antenna the D1 mini Pro should have better WiFi reception than his little brother.

Another difference is the size of the flash memory. In comparison, the D1 mini Pro has 16 MByte of flash memory whereas the D1 mini only has 4 MByte.

D1 mini compatible shields

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Wemos provides a wide range of pre-build extension shields for the D1 minis. There is a wide range of LED, OLED, TFT and ePager display boards for interactive projects.

Various types of environmental sensors are available. You can choose from simple temperature & humidity sensors, air quality sensors or a standard PIR sensor. Next to the sensor shields Wemos also has a selection of motor driver shields for different areas of applications.

If you can't find a suitable shield for your project, Wemos offers so-called base shields. These are empty prototyping boards for your DIY projects. They are available in different form factors (1x, 2x & 3x) and can also be used to stack other shields.

D1 mini compatible shields

All shield boards typically come with male and female pins are already included in the package. A full list of official shields can be found on the Wemos Wiki.

ESPHome & the D1 mini boards

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ESPHome works on top of PlatformIO which has support for a wide range of ESP8266, ESP32 and various other development boards. Wemos D1 boars are supported as well, to use them in your ESPHome projects use:

esphome:
	platform: ESP8266
	board: d1_mini

---- or ----

esphome:
	platform: ESP8266
	board: d1_mini_pro

Or use the short form:

esp8266:
  board: d1_mini_pro

I recommend to always use the Wemos specific board name instead of a generic esp board or board: nodemcuv2. While these might work as well the pin mapping might be mixed up and you will get unexpected behaviour.