Edimax EW-7811Un 150Mbps 11n Wi-Fi USB Adapter, Nano Size Lets You Plug it and Forget it, Ideal for Raspberry Pi / Pi2, Supports Windows, Mac OS, Linux (Black/Gold)

I tried for days to get this configured. Here is so much conflicting information out there. Finally I found a script to automatically install it. Here are the instructions:Installing your rtl8188cus wireless adapter:--------------------------------------------If you are installing your first wifi adapter or adding a new wifi adapter to a Pi thatalready has a different one installed the driver should be installed BEFORE plugging in thenew wifi adapter.DO NOT PLUG IN THE WIFI ADAPTER UNTIL ASKED TO - LOOK AT THE SCREEN OUTPUT FOR INSTRUCTIONS.So connect up your Pi then power on and wait for it to boot and initialise. Log in and thenyou can start to install the software/firmware for the wifi adapter.Some images need configuring when they are first run so go through the configuration beforerunning the sript. After the image is configured you can start the script to install the wifi.If you have an internet connection to your Pi you can now download the script. Use thecommand:sudo wget http://dl.dropbox.com/u/80256631/install-rtl8188cus-latest.sh -O /boot/install-rtl8188cus-latest.shThis will install the script in the /boot directory of the SD card ready to run.If you are NOT logged in as root start the script using the command:sudo /boot/install-rtl8188cus-latest.shIf you are logged in as root use the command:/boot/install-rtl8188cus-latest.sh (no sudo!)If you are connected to the Pi using ssh, and not logged in as root user then you may needto use the commandsudo bash /boot/install-rtl8188cus-latest.shor if logged in as the root user.bash /boot/install-rtl8188cus-latest.shThe script should now start running. I have written the script so it will output messages tothe screen so you can see what it is doing as a lot of the time there is no output to thedisplay.If you have not used the script before it will make an update to the kernel configurationto allow you to run with the wifi adapter plugged in before the driver is loaded. Thisconfiguration change will disable a built in driver that does not work and causes problemsif the wifi adapter is plugged in before the working driver is installed. After making thechange it will shutdown the Pi. You can then plug in the wifi adapter and power on againand thePi should run without problems. You can then run the acript to install the wifidriver and configure the wifi.At the beginning of the installation the script will make several checks. It will check ifyou have an internet connection, wired or wireless, and you have access to the internet. Itwill try and determine if you already have a wifi adapter configured.If you do not have an internet connection to your Pi it will check it has all the necessaryfiles to install and run the wifi driver. If it does not have all the files it needs it willoutput a list of files it does not have and will abort the installation. You will have todownload the files it requires and copy them to the /boot directory of the SD card andrestart the script.For some images it may be necessary to install some additional applications to allow thewifi to operate correctly. The script will install these before configuring and installingthe wifi driver. If your Pi doesn't have an internet connection and these files are notcopied to the SD card the script will list the files it needs and then abort. You will needto download and copy these files to the /boot directory of the image.To copy missing files to the Pi there are basically two ways to do it. You can shutdown thePi, remove the SD card and plug it into the computer used to generate the image in the firstplace. Then download the missing files on that computer and copy them to the SD card.Alternatively you can download the files needed on another computer with internet access andthen copy them to a USB stick. You can then install the USB stick in the Pi and copy them fromthe USB stick to the SD card. To copy files to the /boot directory you will need to run thecommands as root user. As I understand it a USB stick would normally be automatically mountedin the directory /media. The commandls /mediashould then show the device name. You can then copy the files using the command formatsudo cp /media/device-name/filename /bootI have, however, found that devices are not always mounted automatically so you must firstmount the device manually. Using the commandsudo mount /dev/sda1 /mntwill mount the device in the /mnt directory rather than /media. The files can then be displayedwith the commandls /mntYou can then copy the files using the command formatsudo cp /mnt/filename /bootWhen finished copying the necessary files do not forget to unmount the USB stick -sudo umount /dev/sda1Once all the files are copied to the SD card restart the script. It will again check all thefiles needed are available on the SD card and then start the install.If you already have a wifi adapter installed it will ask if you want to update the driver oradd a new wifi adapter. If you are using an image that already has the rtl8188cus driverinstalled and it no longer works because you have made a software update you can update thedriver to repair the driver installation. If a wifi driver is already installed, eitherusing a different driver or the rtl8188cus driver, you can add another wifi adapter. You canthen use either adapter or even use both. You can use this option to install a new wifiadapter if you don't want to use your old adapter, although the Pi will still be configuredto run the older adapter if necessary.After the driver and any other files needed are installed the script will then configure thefiles needed to use the wifi. It will first ask you the type of security the network uses ifany. eg unsecured, WEP or WPA/WPA2. It uses this to determine some of the settings neededfor the installation and whether you need to input a PASSWORD. The script will not ask for apassword if you selected unsecured as the network security.The script will then ask you to input the network SSID and a PASSWORD if it is required.Type in the SSID and then the PASSWORD. These values will be copied to the file/etc/network/interfaces as part of the setup. When inputting the SSID and PASSWORD thescript will ask you to verify that they are correct before using then.A recent addition to the script is a check to see if the wifi network you want to connect tois visible by the wifi adapter - that is it is transmitting it's ssid. With the basic setupused by the script a wifi adapter will not be able to connect to a network that does nottransmit it's ssid. When the script gets to the point where it asks for the ssid of thenetwork you want to connect to it will check the name is in this list. If it is not it willlet you know. To get a connection you should reconfigure your wireless network to transmitthe ssid.Once the SSID and PASSWORD have been input and verified OK the remaining files will beconfigured to ensure the driver module is automatically loaded whenever the Pi is restarted.The wifi driver should now be installed and configured. The script will output a messageasking you to plug in the wifi adapter. Plug in the wifi adapter and press any key tocontinue.It will wait for the wifi to connect then output some information about the networkconnection. It will show details on the wireless setup and should show you the IP addressassigned to the wireless adapter. You can terminate the installation at this point bypressing Cntl-C.If you do not terminate the script it will then continue on and update the software packageslist and upgrade the installed software packages. This can take a long time especially ifyou are using any of the older images.The script will then install rpi-update if it is not already installed. The rpi-updatescript, developed by Hexxeh, updates the Pi firmware/software.The script will now check if the driver that is loaded is the latest available or not. Ifthe installed driver is the latest the script will terminate and the wifi should be working.If the driver is not the latest version rpi-update will be run to update the Pi'sfirmware/software and then the final stage of the installation is to update the wifi driverto the latest version.If rpi-update is run by the script when the script terminates the Pi will reboot. If rpi-update does not run the script will just terminate and you can continue to use the Pi.When it has rebooted, login - AND START TO HAVE SOME FUN.HAVE FUN WITH YOUR RASPBERRY PI.

I really was expecting these to be a failed purchase. I thought I'd give them a go almost as a novelty... I feel silly now, as they are brilliant. Driver dependency is heavy, don't expect to just plug them in and go as some of the larger clunkier ones would allow with onboard drivers or the ability to use generics. But really it would be kind of giddy to assume otherwise with these things that are so small as to seem unlikely to be effective in any real-world applications.I would do a pro / con, but have no cons.... Perhaps because I just expected the worst, leaving me with nowhere to go but up.- Size: Tiny - I can *almost* close the USB flap on a Dell Duo Convertible with the thing in. I would forget they were in a USB hub if not for the flashing LED. They are practically nonexistent in a tower USB port, front or back.- Reliability: I have used them in odd situations, and have yet for them to be the source of an issue. Mixed NIC environments present the usual hazards, but nothing additional that I've noticed.- Range: Again, I have had low expectations, and so I used them mostly so close to the wireless source that I couldn't judge fairly. They have fit the bill at 25+ feet from the nearest active AP handily. Walls and obstacles have not buggered the connectivity. That's more than I would have expected, your situation may differ.- Price: Cheap, especially considering the awkward situations that they can be used to resolve temporary issues and the time sink potential in those situations if you don't have a quick-and-dirty answer. I will likely keep a small stack of them around indefinitely.So far I have used these in scenarios like:- Emergency connectivity for DNS server mishaps on domains- A replacement for troublesome hard-connections in nearby Win 7 64 workstations- As a makeshift NIC array via a USB hub for Windows 2008 R2 Datacenter servers requiring multiple connections but lacking the hardware- Onboard fail-safe connection (by pluging one into the unusually placed USB slots on Dell and Supermicro server boards, just leaving them there,disabled or otherwise inactive, just in case all other options are bunk)- Near invisible wireless connections on Netbooks, Dell Duo Convertibles, Legacy laptops.I can't attest fully to their cross platform usage yet. But I have several unusual server and wokrstation builds across the SUSE and Ubuntu spectrum that I will certainly be giving them a test on. I have a pretty fair expectation that as long as the drivers install as expected, they will be effective there too...I have used them as a guest captured NIC for Linux and Windows virtual appliances and servers with some success, but as there is a significant abstraction layer there, that doesn't seem like an overall statement about their usage in a standalone environment.So this is one of those times when a shot-in-the-dark actually has paid off in volume... I would (and will) purchase more of them, either for specific applications or more likely as a brilliant addition to my "what if" toolset.If there is a downside, I haven't found it yet...and I have used them in some pretty weird circumstances so far... There may well be better out there, I just stumbled on these, didn't really invest in thorough product research. I grabbed some of these along with other variant wireless and USB NICs for emergencies and peculiar issues.These are the ones I have used almost every time. The rest of that collection of variants remain safely boxed on the shelf.