An Ethernet Arduino® is any pairing of an Arduino® board with a Ethernet port. This pairing is usually accomplished by using a microcontroller with an integrated Ethernet port or by adding an Ethernet shield to another board. Arduino® is an open source microcontroller platform designed for hobbyists and professionals to use in the rapid creation of electronic devices. Ethernet Arduino® devices add high speed network capabilities to that platform.
Ordinary Arduino® devices are equipped with Universal Serial Bus (USB) or serial connections. Adding a network connection allows these devices to transmit data at a much higher rate than normally possible. Webduino is a software package that allows the microcontroller to run a webserver using an Ethernet connection. This webserver hosts a site on the microcontroller that can be used to upload data from the device, remotely control it, or both. Webduino with Ethernet is particularly useful for remotely accessible sensor arrays.
In addition to web hosting, there are several other uses for the high speed connection offered by the Ethernet Arduino®. Webcams, for example, are easily manageable through a Ethernet-enabled device, but impossible using many slower connections. Other devices take advantage of the bandwidth to transmit or relax other transmissions; for example, a Ethernet Arduino® that was also equipped with both a wireless receiver could monitor wireless activity in an area inaccessible to the computer or base station to which it was connected. The device would be different from a simple repeater in that it could execute complex processing on the signals it monitored, determining what action to take on a case-by-case basis.
Along with these advantages, Ethernet Arduino® comes with some significant limitations. In order to transmit at those rates, the device must be connected to a networking cable. The cable is relatively stiff, making the platform unsuitable for most mobile applications. Remote control robotic projects are nearly impossible. In cases of a mobile device, a Ethernet Arduino® is only desirable when the machine in question needs a high speed connection when it is not in motion.
Other Arduino® interface options include serial and USB connections, as well as wireless protocols like WiFi® and XBee®. USB and Serial connections are most commonly used with devices that only need connections for occasional reprogramming. Devices that require a constant connection but also need to maintain mobility are generally equipped with wireless interfaces. These interfaces are also used in cases where a wired connection is impractical or impossible, such as an outdoor weather station that needs to report data back to an indoor computer or other device. Despite having fewer restrictions than Ethernet, inventors sometimes avoid wireless interfaces because of their higher cost and energy consumption.