Setting up Wifi (EDIMAX) on Raspberry Pi

This post is adapted from http://kerneldriver.wordpress.com/2012/10/21/configuring-wpa2-using-wpa_supplicant-on-the-raspberry-pi/

First you need to see if the EDIMAX usb Wifi is recognized by using command

lsusb

Once you see the device connected, edit the file /etc/network/interfaces (requires root)

....

auto wlan0
allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf

iface default inet dhcp

Then edit /etc/wpa_supplicant/wpa_supplicant.conf (requires root):

network={
    ssid="Your SSID Here"
    proto=RSN
    key_mgmt=WPA-PSK
    pairwise=CCMP TKIP
    group=CCMP TKIP
    psk="YourPresharedKeyHere"
}

After that, you will need to bring up the “wlan0″ interface using “ifup” (requires root):

$ sudo ifup wlan0

You may see the following messages like this:

ioctl[SIOCSIWAP]: Operation not permitted
ioctl[SIOCSIWENCODEEXT]: Invalid argument
ioctl[SIOCSIWENCODEEXT]: Invalid argument

You may ignore the messages but the adapter should be usable now