Wemos D1 mini User Manual

Wemos D1 mini is an ESP8266 board that’s interesting thanks to its size, its low price ($4), micro USB
power, its shields, and a documentation that looks fairly good. The board can be programmed with
Arduino or Lua, and supports both serial and OTA programming. I’ve decided to give it a try and bought
the board together with two temperature shields, a relay shield, and micro SD shield.
Click to Enlarge
I got all for $ 14.00 from Wemos Aliexpress shop, and it took about one month for delivery. I can also see
they’ve recently released a new OLED shield selling for about $5. All shields were shipped inside their
own anti-static bags.
The pins are clearly marked on both side of the board and the shields. One side of the board features
ESP8266 module.

Wemos D1 mini Specifications

General

Microcontroller	ESP8266
Operating Voltage	3.3V
Digital I/O Pins	11
Flash Memory	4 MB
SRAM	64 KB
Wi-Fi Standard	802.11 b/g/n
USB Interface	Micro USB
Dimensions	34.2mm x 25.6mm
Analog Input Pins	1
Clock Speed	80 MHz

Summary

Wemos D1 Mini Introduction and Hardware Overview

Wemos D1 Mini Board Details

Details the ESP8266 module, CH340 chip, and pin layout on the Wemos D1 mini board.

Shield Stacking and Assembly Considerations

Explains how to stack shields and highlights potential soldering pitfalls for proper alignment.

Arduino IDE Setup for Wemos D1 Mini

Installing Arduino IDE and Board Support Files

Covers installing Arduino IDE, cloning ESP8266 board support, and connecting the Wemos D1 mini to the computer.

Configuring IDE Settings and Board Selection

Details selecting the 'WeMos D1 R2 & mini' board and configuring settings like CPU frequency and flash size.

Wemos D1 Mini Shield Examples and Usage

DHT Pro Shield: Temperature and Humidity Monitoring

Explains the DHT Pro Shield sample code for reading temperature and humidity, including setup, data retrieval, and output interpretation.

Resolving DHT Library Compilation Errors

Addresses the error of a missing DHT library and provides steps to install it via the Library Manager.

Relay Shield: Blink Example and Operation

Demonstrates the Relay Shield's functionality with a blink sketch, showing its operation and concurrent use with other shields.