subject: Connecting Your Designs To The Web Using The Ethernet Shield When You Need To Go Live [print this page] Almost every electronic device with a screen these days has some call to be connected to the internet. In Arduino this is done using an Ethernet shield, which allows your device to contact and receive information from an IP address or server.
To start off, you need the shield itself. The shied is connected to the Arduino board using wire, which snakes down through holes in the middle of the relay board and wraps around header pins on the main Arduino. This neat little design trick leaves the whole face of the Ethernet shield available for tertiary connections, so you can stack other boards on top of it with ease.
The Ethernet library is required in order for you to write the scenes that let your device do what you want it to do when it connects to the web. There are several classes available in the Ethernet library, all of which have specific effects on the end functioning of your device.
The Ethernet class activates the library and calls up the network settings for the device. The IP Address class then works in tandem with either remote IP addresses or local ones so your device can plug properly into the network.
The Server class uses the Ethernet shield to create servers. So you can use the shield to build your own server capable of sending and receiving data from clients. A client in this sense being defined as a program hosted on another device, or someone else? computer.
Client class creates clients, rather than servers clients are typically devices that need to upload and download data from servers. While the server you created with the Server Class is normally a device used to store and pass on data in other words it has no end user function and is simply used as a heart or brain for a network. Storage is done on servers action takes place through clients.
There is also an Ethernet UDP class, which allows you to send and receive Ethernet UDP messages.
The Ethernet shield from Arduino lets the user connect with as many as four socket connections (simultaneously).
Internet connections are as common as mice these days, so the Ethernet board is something you should probably always have in your stack of useful bits and pieces. Certainly, if you are interested in any way in delivering or developing handheld devices like smart phones, GPS or even just a simple mobile emailing device, you need the ability to turn your project into a client capable of taking information from the net.
To use the Ethernet shield to make a server, you can use its incorporated micro SD card slot for storing the files you need to serve. The micro SD slot gives you a theoretically unlimited memory capacity obviously you are limited by the capacity of the micro SD card you use, but as micro storage continues to get bigger this should present no real problems for your end user, or your project.
