title: Red Pitaya WiFi adapter Edimax EW7811U
body: <p>This is a comment to a previously asked question related to the EW7811U WiFi adapter (the topic was closed so I cannot answer directly). I have the same Edimax EW7811U adapter and here is how I got it working with Red Pitaya and my WPA2-protected 802.11n network. </p>
  
  <p>First shut off the Red Pitaya, remove the memory card and connect it to a PC (I used the adapter that came with the memory card and inserted into the memory card slot in my laptop).</p>
  
  <p>Edit the file /etc/network/wpa_supplicant.conf and insert the ssid and psk strings: </p>
  
  <pre><code># WPA2 configuration example
  network={
     ssid="ssid-string"
     psk="password-string"
     proto=WPA2
     key_mgmt=WPA-PSK
     pairwise=CCMP
     group=CCMP
     auth_alg=OPEN
  }
  </code></pre>
  
  <p>Save the file and put the memory card back into Red Pitaya and restart.</p>
  
  <p>In my console I can see that the wlan0 interface is initialized and that the DHCP client gets an IP address:</p>
  
  <pre><code>++ Bringing up wlan0
  Successfully initialized wpa_supplicant
  rfkill: Cannot open RFKILL control device
  ioctl[SIOCSIWAP]: Operation not permitted
  udhcpc (v1.20.1) started
  Sending discover...
  Sending discover...
  Sending discover...
  Sending select for 192.168.11.115...
  Lease of 192.168.11.115 obtained, lease time 43200
  </code></pre>
  
  <p>You can check the interface status with iwconfig:</p>
  
  <pre><code>redpitaya&gt; iwconfig
  wlan0     IEEE 802.11bgn  ESSID:"my-ssid"  Nickname:"&lt;WIFI@REALTEK&gt;"
        Mode:Managed  Frequency:2.412 GHz  Access Point: 20:C9:D0:1D:AB:CD   
        Bit Rate:150 Mb/s   Sensitivity:0/0  
        Retry:off   RTS thr:off   Fragment thr:off
        Encryption key:****-****-****-****-****-****-****-****   Security mode:open
        Power Management:off
        Link Quality=100/100  Signal level=83/100  Noise level=0/100
        Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
        Tx excessive retries:0  Invalid misc:0   Missed beacon:0
  </code></pre>