Raspberry Pi - Installing the Edimax EW-7811Un USB WiFi Adapter (WiFiPi)
Saturday, October 20, 2012 at 5:23PM
Robert Savage in 802.11, EW-7811, Embedded Computing, Networking, Raspberry Pi, Raspberry Pi, edimax, pi, raspberry, raspi, usb, wifi, wifipi, wireless

The Edimax EW-7811Un 150 Mbps Wireless 802.11bgn USB Adapter is a popular choice for use with the Raspberry Pi.  Here is what this little adapter has going for it:  

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Packaging / Specs

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The latest Raspian distribution (Raspbian “wheezy” 2012-09-18) already includes the drivers for this adapter pre-installed.  This greatly simplifies the installation.  (If you are using a different distribution or an older distribution you may have to install the Linux driver for the Realtek RTL8192CU driver.)

Insert the Edimax USB adapter into your Raspberry Pi's USB port.   Next, lets make sure that the Raspberry Pi recognizes the device.  Use the following command to verify that the Pi "sees" the Edimax WiFi adapter.


You should see the Edimax EW-7811Un device listed in the output.

Now that we have verified that the Edimax adapter is recognized, lets check to make sure the kernel driver is loaded.  Use the following command to list the kernel modules:


You should see the "8192cu" kernel module loaded.  If not, try removing and re-inserting the Edimax USB adapter. 

As a final validation check to make sure that the Edimax is ready to use, send the "iwconfig" command to display a listing of the current wireless network configuration. 


We are just looking to ensure that the "wlan0" adapter is present.

Now we are ready to move on to the configuration steps.


One you have installed the adapter, verified the kernel driver is loaded, and confirmed that a wireless network interface ("wlan0") is available, you will need to configure the wireless connection settings to securely connect to your wireless network.

First, let's open the network interfaces configuration file for editing using the following command:

sudo nano /etc/network/interfaces

Make sure the following lines are added to (or un-commented in) your file

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


After modifying the network interface configuration file, we need to create the wireless configuration file. Use the following command to create (or edit) this file.

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

Add the following data to this wireless configuration file. (Replace the "_SSID_" and "_WPA_SHARED_KEY_" text with your actual SSID and WPA key values.)

pairwise=CCMP TKIP

(Note:  This configuration is intended for WPA protected wireless networks.)

Once the configuration files are complete, use the following command to restart the wireless adapter / interface.

sudo ifup wlan0

This command will restart the network interface and use the newly defined interface and wireless settings to establish a wireless network connection.  Assuming the configuration is correct, the wlan0 interface should connect and acquire an IP address.


For connection verification and an alternate way to see your assigned IP address, use the following command to list the network configuration:

ifconfig wlan0

If you have any trouble getting connected using the "ifup" command, verify your wireless connection settings and reboot your Raspberry Pi.  If you have the Raspberry Pi connected to a display you can watch the Pi attempt the connection during startup.  

That's it, hopefully you now have a WiFiPi.

* Raspberry Pi is a trademark of the Raspberry Pi foundation.

Also check out the installation instructions for installing and configuring the

>> Airlink 101 Wireless N 150 Ultra Mini-USB Adapter (AWLL5099)

The following article is an excellent resource describing many different wireless network configurations for Debian based distributions: 
Article originally appeared on SHA (http://www.savagehomeautomation.com/).
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