Using a Realtek 802.11n dongle with Unipi

killua

Setting up some Unipi's to talk to a central (HA/scalable) server here. Since wired as well as wireless connection to the unipis was required, we got a few Realtek wifi dongles. Follows a braindump to recall it later and free for anyone else to use.

Lets get the kernel modules first:

wget http://www.mendrugox.net/downloads/20 -O raspi
scp -r raspi pi@192.168.2.222:~

SSH into the RPi and to load the module

sudo su
cd raspi
sudo cp *.ko /lib/modules/3.12.28+/kernel/drivers/net/wireless/
sudo cp *.bin /lib/firmware/rtlwifi/
sudo depmod -a
sudo echo 8188eu >> /etc/modules
sudo modprobe 8188eu

Now, we want the RPi to acquire a fixed IP (192.168.2.222) when connected to LAN and use the GW 192.168.0.1 and we also want the RPi to lease an IP from DHCP when wifi dongle is connected to it. To do this, we want to change /etc/network/interfaces accordingly:

sudo echo '
auto lo

iface lo inet loopback
iface eth0 inet static
address 192.168.2.222
netmask 255.255.255.0
gateway 192.168.0.1

allow-hotplug wlan0
auto wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp
' > /etc/network/interfaces

We need to setup wpa supplicant. Assuming your wifi has the ssid "MYSSID" and password "YOUSHALLPASS", then

sudo wpa_passphrase MYSSID YOUSHALLPASS

whcih reutrns

network={
        ssid="MYSSID"
        #psk="YOUSHALLPASS"
        psk=74d000273e94452d31a3e0ec32d87b8ac52dd3e31f1448a41b8d98ea99abafa0
}

which you need to put into your wpa_supplicant.conf. The complete conf file looks like this

sudo echo '
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
        ssid="MYSSID"
        #psk="YOUSHALLPASS"
        psk=74d000273e94452d31a3e0ec32d87b8ac52dd3e31f1448a41b8d98ea99abafa0
        key_mgmt=WPA-PSK
        pairwise=CCMP
        auth_alg=OPEN
}
' >  /etc/wpa_supplicant/wpa_supplicant.conf

To prevent the dongle to go to sleep whenever you don't need it, disable power management:

sudo echo '
# Disable power management
options 8192cu rtw_power_mgnt=0 rtw_enusbss=0
' > /etc/modprobe.d/8188eu.conf

If you still get random disconnects, get closer to your AP (that actually helped, the dongle is crap when it comes to signal strength). Hope this helps.

killua