superfilin
Posts: 1
Joined: Sat Feb 02, 2013 7:12 pm

Can't connect to WiFi with EDIMAX EW-7811UN

Sat Feb 02, 2013 7:44 pm

Hi guys!

I got my Raspberry Pi a couple of weeks ago and installed the very recent image of Raspbian Wheezy (2012-12-16-wheezy-raspbian) on SD Card.

After successful start up and connection I did:

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sudo apt-get update 
sudo apt-get dist-upgrade
sudo apt-get upgrade
I also ran sudo raspi-config and did some minor changes for password and additional languages. Everything just worked perfectly.

Then a few days ago I got EDIMAX EW-7811UN (USB WIFI Nano Dongle) and finally found some time to try it out. But I can't connect it to my WiFi network. I can't even get it to list available networks. I feel that I'm doing something wrong and that I must very close. Here are some details.

lsusb command lists the device properly:

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[email protected] ~ $ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
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]
lsmod command shows that module for the RTL8188CUS chipset is loaded, but is not used by anyone:

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[email protected] ~ $ lsmod
Module                  Size  Used by
snd_bcm2835            12808  1
snd_pcm                74834  1 snd_bcm2835
snd_seq                52536  0
snd_timer              19698  2 snd_seq,snd_pcm
snd_seq_device          6300  1 snd_seq
snd                    52489  7 snd_seq_device,snd_timer,snd_seq,snd_pcm,snd_bcm2835
snd_page_alloc          4951  1 snd_pcm
8192cu                485042  0
I also changed the /etc/network/interfaces to look like this:

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auto lo

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
auto wlan0
iface wlan0 inet dhcp
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
And added my network to the wpa_supplicant.conf

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ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
  ssid="..."
  proto=RSN
  key_mgmt=WPA-PSK
  pairwise=CCMP TKIP
  group=CCMP TKIP
  psk="...."
}
I rebooted the device serveral times, but still WiFi is not activated. WLAN configuration shows that wlan0 exists:

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[email protected] ~ $ iwconfig wlan0
wlan0     unassociated  Nickname:"<[email protected]>"
          Mode:Auto  Frequency=2.412 GHz  Access Point: Not-Associated
          Sensitivity:0/0
          Retry:off   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality:0  Signal level:0  Noise level:0
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0
But scanning for networks gives no results (and I know I have plenty of networks around including mine):

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[email protected] ~ $ iwlist scan
lo        Interface doesn't support scanning.

wlan0     No scan results

eth0      Interface doesn't support scanning.
Also tried sudo ifconfig wlan0 up command, but still it does not give any results.
Any idea of what I'm doing wrong?

pjc123
Posts: 913
Joined: Thu Mar 29, 2012 3:37 pm
Contact: Website

Re: Can't connect to WiFi with EDIMAX EW-7811UN

Sun Feb 03, 2013 1:02 pm

I can't speak for whether the settings in your wpa_supplicant file are correct for your specific router, but:

This portion of code is incorrect in your /etc/network/interfaces file:

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iface wlan0 inet dhcp
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
It needs to be the following for your particular configuration:

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iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp
Notice the word "manual" and the addition of the last line.
My Raspberry Pi Project Page:
https://www.flaminghellmet.com/launch/

spuech
Posts: 8
Joined: Sat Feb 02, 2013 6:45 pm

Re: Can't connect to WiFi with EDIMAX EW-7811UN

Sun Feb 03, 2013 1:23 pm

I've got the same adapter as you and I can't connect into my wireless network. Wpagui says that i'm connected, but shows no ip adress and when i'm trying to connect with dillo to the net, i got the error : "DNS can't resolve google.com".

Here are my configuration files :
etc/wpa_supplicant/wpa_supplicant.conf

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
ssid="..."
psk="..."
proto=RSN
key_mgmt=WPA-PSK
pairwise=TKIP
auth_alg=OPEN
}

and etc/network/interfaces

auto lo
iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplican.conf
iface default inet dhcp




I'm using a wheezy distribution for raspberry pi and my network is encrypted with WPA2(TKIP/AES).

Thanks for helping

DBryant
Posts: 281
Joined: Sat Feb 02, 2013 12:41 pm
Location: Berkshire, UK

Re: Can't connect to WiFi with EDIMAX EW-7811UN

Wed Feb 06, 2013 9:01 am

Is your adapter powered off the Pi itself?

My system only started working when I used powered USB hub for adapter, despite the fact it was described as lower power and would function in a basic configuration.

And now its all working i.e config is known to be correct etc., it still does not function in the Pi.

Notes to myself at the time:

iwlist wlan0 scan
wlan0 No scan results

No mileage until used a powered USB hub; the wireless adapter is running hot.
So installing the adapter in the USB hub and powering the Pi off it as well, find local networks straight away:

iwlist wlan0 scan
wlan0 Scan completed :
Cell 01 – Address: ....
...

spuech
Posts: 8
Joined: Sat Feb 02, 2013 6:45 pm

Re: Can't connect to WiFi with EDIMAX EW-7811UN

Thu Feb 07, 2013 4:42 pm

Yes, my wifi adapter is connected directly to a powered usb hub. The pi found my wireless network, but sometimes it connects to it, sometimes not.

DBryant
Posts: 281
Joined: Sat Feb 02, 2013 12:41 pm
Location: Berkshire, UK

Re: Can't connect to WiFi with EDIMAX EW-7811UN

Thu Feb 07, 2013 5:01 pm

You seem to have hi-jiacked someone elses thread!

If you have an intermittent problem looker at the logs on your Pi, they're in /var/log and see if you can see any fault there. You can run wpa_supplicant form the command line and get it quite chatty with the -v flag.

Also take a look at the logs on your router, you may have to enable them, and that may also shed some light.

MrRicheyRich
Posts: 10
Joined: Fri Sep 21, 2012 3:39 pm

Re: Can't connect to WiFi with EDIMAX EW-7811UN

Thu Feb 07, 2013 5:15 pm

I had a similar problem with the most recent distribution of Raspbian. If you can get a hold of the September 2012 release of Raspbian, have a try because my Edimax worked for me then.

If you can't find it then install RaspBMC instead - that worked with my Edimax dongle straight out of the box.

If either of those distributions work then it will have confirmed that there's something wrong with the latest Raspbian for Edimax wireless dongle users...

Rich

spuech
Posts: 8
Joined: Sat Feb 02, 2013 6:45 pm

Re: Can't connect to WiFi with EDIMAX EW-7811UN

Thu Feb 07, 2013 5:43 pm

I found it : for me it was a little mistake.

There was written wpa-supplicant/wpa_supplicant.conf

and it was wpa_supplicant/wpa_supplicant.conf

Thanks for having helped me

selethd
Posts: 1
Joined: Sat Feb 09, 2013 6:33 pm

Re: Can't connect to WiFi with EDIMAX EW-7811UN

Sat Feb 09, 2013 6:40 pm

To the original poster, I was having the same issue as you, and I have the exact same setup, but use a belkin wireless adapter.
When I did the 'iwlist scan' command, I didnt see any wireless networks, however
when I did 'sudo iwlist scan' command, it did show my wireless network... as well as others.

However, now my only problem, is that I cant seem to get my wireless to 'connect' to my network. I have other wireless devices like cell phone, and laptop that connect properly, but I dont know what to do to get the pi to connect to it.

If you have found a solution or you get yours working, please post what you did. Thanks

markhas
Posts: 1
Joined: Sun Feb 10, 2013 8:33 pm

Re: Can't connect to WiFi with EDIMAX EW-7811UN

Sun Feb 10, 2013 9:19 pm

After buying a full kit from maplins, i logged on to my wireless network on the first attempt.after 2 days i was left looking @ all the forums as the pi now would not connect,trying all the things u have mentioned i was ready to give up,no joy from maplins, staff were very helpful, swapping all the parts, working with 12volts and less for a living i decided to check the power loss with each component plugged in and out, to my surprise it was the wireless dongle/adapter, very Hungary for voltage to say it is said to be low powered? NOT.having only 5volts on start up, i then decided to order a new power supply from PI HUT, it as 5 volts and 1500 milliamps,not like the one with the kit, 5 volts 1000 milliamps. Testing the PI was not as described, on the new model the + terminal as moved so with the protective case on the holes are in the wrong place, PS be careful its near the SD card terminals,now the PI connected now problem, the voltage drop was now staying @ 5.2 volts,anything below 4.85 was no good to connect to the wireless network.

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