I literally spent 10 hours trying to get the Edimax EW-7811UN wifi adapter to work with my model B pi. My searching for answers wasn’t very fruitful, until I realized the problem was related to the fact that my wireless network SSID is hidden. So, I wanted to share my experience here in case it helps someone.
I’m using the 2012-10-28 wheezy distribution. By all accounts, the wifi was supposed to work out of the box with the Edimax wifi. It did not work for me.
Specifically, it would not associate with my wireless network that I configured in the wpa_gui (this is the tool that runs when you open “Wifi Config” from the desktop. After adding my network in the wpa_gui, the /etc/wpa_supplicant/wpa_supplicant.conf file looked like:
No amount of hacking the config, rebooting, etc. would make it associate. So I started removing the password protection on my network, etc.. It turns out that the default setup doesn’t work with a hidden network, which mine was.
You have to add the scan_ssid=1 to the /etc/wpa_supplicant/wpa_supplicant.conf file so it looks like:
Once I did that, and rebooted, it associated just fine.
Hope this helps someone,