The Arduino Ethernet Shield R3 allows an Arduino board to connect to the internet. Based on the Wiznet W5100 Ethernet chip, it provides a full TCP/UDP network stack supporting up to four simultaneous socket connections. Use the Ethernet library to write sketches that connect to the internet.

This assembled revision includes a micro-SD card connector for serving files over the network, MEGA compatibility, and an on-board reset controller. The shield connects via long wire-wrap headers that preserve the Arduino's pin layout and allow additional shields to be stacked on top.

Key Features

• Wiznet W5100 Ethernet Chip – Full TCP and UDP network stack with up to 4 simultaneous socket connections
• Standard RJ-45 Connector – Reliable wired ethernet networking
• Micro-SD Card Slot – Store and serve files over the network
• Stackable Design – Long wire-wrap headers maintain pin layout and allow shield stacking
• On-Board Reset Controller – Ensures proper module initialisation on power-up
• SPI Communication – Uses digital pins 10, 11, 12, and 13 (these pins cannot be used for general I/O while the shield is active)

Ideal For

• IoT projects requiring wired internet connectivity
• Web servers and network-connected data loggers
• Remote monitoring and control systems
• Projects where Wi-Fi is unreliable or unavailable

Resources

• Arduino Ethernet Shield Product Page
• Getting Started Guide
• Ethernet Library Reference