The Wemos D1 Mini is a compact WiFi-enabled development board based on the ESP8266, blending Arduino compatibility with native IoT capabilities. Unlike traditional Arduinos, it integrates 2.4GHz WiFi while costing less than an Uno+WiFi shield combo.
Key Advantages
✔ Built-in WiFi (STA/AP/STA+AP modes)
✔ 4MB Flash (vs. Uno's 32KB) for OTA updates
✔ Arduino IDE Compatible via ESP8266 core
✔ Micro-USB Programming (no external adapters)
Performance & Memory
80MHz CPU (160MHz achievable) – 5x Uno's clock speed
64KB+32KB RAM for complex network operations
4MB Flash stores web pages, SPIFFS filesystem
Connectivity & Expansion
11 Multiplexed GPIOs (note: some restrict boot modes)
Software I2C/SPI (hardware SPI available)
ADC Pin for battery monitoring (0-3.3V range)
Power Efficiency
Deep Sleep Mode (~20μA) for battery projects
Onboard 3.3V Regulator powers sensors directly
Applications
IoT Sensors (MQTT/HTTP to cloud platforms)
Smart Home Devices (ESPHome, Tasmota)
WiFi-Enabled Prototypes (replace Uno+WiFi shield)
MQTT Clients (Home Assistant integrations)
Package Includes : 1 x Wemos D1 ESP8266 WiFi Board