Get started with the Arduino Ethernet Shield 2

What it does

The Arduino Ethernet Shield 2 connects your Arduino to the internet using a wired Ethernet connection. Simply mount the shield onto your Arduino board, connect it to your network with a standard RJ45 cable, and use Arduino libraries to send and receive data over the internet.

Specifications

• Operating voltage: 5V (supplied from the Arduino board)
• Ethernet controller: W5500 with internal 32K buffer
• Connection speed: 10/100 Mbps
• Connection with Arduino: SPI port
• RJ45 port: Standard Ethernet jack for CAT5 or CAT6 cables

The W5500 chip handles the TCP/IP stack internally, freeing your Arduino to focus on your application logic. The 32K internal buffer improves network performance for data-intensive applications.

01 Connect the shield

To use the Ethernet Shield 2, mount it on top of your Arduino board (such as the Uno or Mega):

1. Ensure your Arduino board is powered off and disconnected from your computer.
2. Align the shield's pin headers with the Arduino's pin sockets. The shield should fit directly on top of the board.
3. Gently press down until the shield is firmly seated on all pins. Do not force it; if it doesn't fit easily, check the alignment.
4. Once mounted, the shield will draw power from the Arduino board through the stacked connection.

The shield's SPI pins (digital pins 10, 11, 12, and 13 on the Uno) are used for communication. These pins are not available for other uses when the Ethernet Shield 2 is connected.

02 Connect to your network

1. Connect a standard Ethernet cable (CAT5 or CAT6 with RJ45 connectors) to the shield's Ethernet port.

2. Connect the other end of the cable to your network hub, switch, or router.

   Direct computer connection

   If you're connecting the shield directly to a computer instead of a router, you may need a crossover Ethernet cable. Most modern computers and network devices support Auto-MDIX and will work with a standard cable.

03 Upload a sketch

1. With the shield mounted, connect your Arduino board to your computer using a USB cable as you normally would for programming.

2. Open the Arduino IDE and load an Ethernet example sketch. Go to File → Examples → Ethernet and choose a sketch such as WebClient or WebServer.

3. Upload the sketch to your Arduino. Once uploaded, you can disconnect the USB cable and power the Arduino with an external power supply if desired.

4. The Arduino will use DHCP by default to obtain an IP address from your router. Check your router's connected devices list to find the Arduino's IP address, or modify the sketch to use a static IP address.

For most projects, an external power supply is recommended when running network-connected applications continuously. The official Arduino power adapter or a suitable DC barrel jack power supply works well.

If it doesn't work

• No network connection: Check that the Ethernet cable is fully seated in both the shield and your router or switch. Try a different cable or port on your router. Look for link lights on the RJ45 jack—they should illuminate when properly connected.
• Sketch won't compile: Ensure you have the Ethernet library installed. It's included with the Arduino IDE by default, but verify it's present under Sketch → Include Library → Ethernet.
• Can't reach the Arduino on the network: Verify your network setup allows DHCP, or configure a static IP address in your sketch. Check your router's firewall settings if you're trying to access the Arduino from outside your local network.
• Pins not aligning: Confirm you're using a compatible Arduino board. The Ethernet Shield 2 is designed for boards with the standard Arduino Uno footprint.