The Arduino Ethernet Shield W5100 is a plug-and-play network expansion shield that allows compatible Arduino boards to connect to a wired Ethernet LAN or internet connection using a standard RJ45 cable. Based on the WIZnet W5100 Ethernet controller, this shield provides a hardware TCP/IP stack and supports common network protocols such as TCP and UDP, making it a practical choice for Arduino web servers, IoT monitoring nodes, data loggers, automation panels and remote control projects. It is designed for popular 5V Arduino-compatible boards including Arduino UNO and Mega 2560 style boards, and communicates with the microcontroller through the SPI interface. This W5100 Ethernet Shield typically includes an onboard RJ45 Ethernet socket with link/activity indication, reset button, stackable Arduino headers, and a MicroSD card slot for local file storage or web-page hosting. The W5100 chip supports up to four simultaneous socket connections, which is useful for compact embedded networking projects. The MicroSD slot can be used with FAT16/FAT32 formatted cards, enabling sensor data logging, configuration storage or serving static files in web-server applications. Powered from the Arduino board at 5V, it is easy to install: stack it on the Arduino, connect a network cable, load an Ethernet library sketch, and begin communicating over a wired network. Ideal for engineering students, hobbyists and DIY electronics makers in India, this shield is a reliable way to add stable Ethernet connectivity where Wi‑Fi is not preferred.
Libraries: Arduino Ethernet library and SD library compatible sketches MicroSD Slot: Yes, for FAT16/FAT32 formatted cards; listings commonly mention support up to 32GB Ethernet Speed: 10/100 Mbps class Ethernet shield listings commonly specify 10/100 Mbps support Arduino Interface: SPI Compatible Boards: Arduino UNO, Arduino Mega 2560 and compatible 5V Arduino boards Network Interface: RJ45 Ethernet port Operating Voltage: 5V from Arduino board Typical Connectors: Stackable Arduino headers, RJ45 socket, MicroSD card slot Ethernet Controller: WIZnet W5100 Supported Protocols: TCP, UDP, IPv4, ICMP as commonly listed for W5100 Arduino shields Maximum Socket Connections: Up to 4 simultaneous sockets
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