Setting up the Edimax Nano on the Raspberry Pi

Finally got the Edimax Nano (EW-7811Un) setup on my Raspberry Pi. Last year I could not get it working but it appears that newer versions of the Raspbian Wheezy image might have simplifed the config. The following instructions worked with the 7/26/2013 Raspbian image (can’t speak for older or newer versions) and WPA (Did not try it for WPA2).

Plug in the adapter and reboot.
Check that the device is showing up (Note the last entry):

pi@raspberrypi ~ $ lsusb
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. 
Bus 001 Device 004: ID 7392:7811 Edimax Technology Co., Ltd EW-7811Un 802.11n Wireless Adapter [Realtek RTL8188CUS]

Edit the /etc/network/interfaces file as follows and reboot:

auto lo

iface lo inet loopback
iface eth0 inet dhcp

auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-ssid "my ssid"
wpa-psk "my wifi password"

See if you’re connected and getting an IP, a blue light should be flashing on the adapter:

pi@raspberrypi ~ $ ifconfig wlan0
wlan0     Link encap:Ethernet  HWaddr 80:1f:02:70:7d:b1  
          inet addr:192.168.1.104  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:911 errors:0 dropped:1014 overruns:0 frame:0
          TX packets:444 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:123537 (120.6 KiB)  TX bytes:74644 (72.8 KiB)

Troubleshooting

See if you can scan for available networks, if so you might have your ssid or password set incorrectly:

pi@raspberrypi ~ $ sudo iwlist wlan0 scan
wlan0     Scan completed :
          Cell 01 - Address: 08:60:6E:E8:DD:64
                    ESSID:"dagobah"
                    Protocol:IEEE 802.11bgn
                    Mode:Master
                    Frequency:2.437 GHz (Channel 6)
                    Encryption key:on
...

Try plugging the adapter into the other USB port on the pi. Was having a terrible time getting it to work, did this and voila!
Make sure you are plugged into a powered hub. I guess this can be a problem as the adapter draws more current than some ports can provide. If you don’t see the blue light flashing on the adapter this might be the issue.
Hit the pi add-ons forum. And don’t ask me in the comments because I’m just as clueless as you.

Setting up the Edimax Nano on the Raspberry Pi August, 2013