Ethernet Shield W5100 – Connect Your Arduino to the Internet with TCP/IP Stack

Expansion Module with 10/100 Mbps Support and microSD Card Slot for Data Storage

The Arduino Ethernet Shield W5100 is an Ethernet expansion board (shield) that enables your Arduino (Uno, Mega2560, Mega1280, etc.) to connect to wired networks using a standard RJ-45 Ethernet cable. Based on the Wiznet W5100 controller, this shield offers a full TCP/IP networking stack with support for common internet protocols and includes a built-in micro-SD card slot for serving files over the network.

Key Features:

• Wiznet W5100 Ethernet Controller: Supports TCP and UDP communication with internal networking stack.

• Up to four simultaneous socket connections — perfect for web servers or multiple clients.

• Standard RJ-45 Ethernet Port with 10/100 Mbps support.

• On-board micro-SD card slot — ideal for storing web content, logs or data files.

• SPI Interface: Communicates with Arduino over SPI (pins 10–13 on Uno, pins 50–52 on Mega).

• Stackable headers: Maintains access to Arduino I/O and allows stacking of additional shields.

• Compatible with Arduino Ethernet library: Supported directly by official Arduino networking libraries in Arduino IDE.

• Network applications: Enables embedded web servers, IoT projects, LAN control devices and remote monitoring.

Use Cases:
✔ Host web interfaces on Arduino.
✔ Log sensor data to SD and serve via network.
✔ Integrate Arduino into home automation systems.
✔ Connect Arduino devices to cloud services.