So you have a neat Arduino project going on. Wouldn't it be nice to add Internet connectivity and do it on the cheap as well? This Instructable will show you how to add Internet connectivity in the form of an Ethernet interface for a few dollars and in less than half an hour. More info at: http://hwstartup.wordpress.com/
Step 1: Order an ENC28j60 Ethernet module on eBay
Apart from your Arduino, you need a read-made Ethernet module. You can easily get these on eBay for as low as 10$. Just search eBay for ENC28J60 module. In addition, you need to have a bit of electrical wire, a soldering iron and some soldering 'tin'.
Step 2: Wire up the Ethernet module
Now it's time to wire up the module. Either use a connector to put on the Ethernet module header or solder straight onto the pins (like I did). You will need just six wires, I used about 3-4 inches length, but this is not critical (as long as it's not a foot long).
Wire up as following (ENC = module side):
- ENC SO -> Arduino pin 12
- ENC SI -> Arduino pin 11
- ENC SCK -> Arduino pin 13
- ENC CS -> Arduino pin 8
- ENC VCC -> Arduino 3V3 pin
- ENC GND -> Arduino Gnd pin
Markings are on the module in white text. The result should look similar to the picture.
If you done this rigt, the LEDs on the module will light up when the Arduino is powered. Stick in an Ethernet cable and the LEDs on the Ethernet connector should light up, showing local Ethernet traffic.