Connect your EV3 to your computer using the mini USB cable or set up the Bluetooth PAN network (both described earlier). Once the connection has been established, SSH into EV3 by running ssh ev3 (or ssh [email protected]).

The first thing we do is confirm that the USB Wi-Fi dongle has been recognized by the EV3, by running ifconfig. The output should contain a block related to the wlan0 interface. To allow the EV3 to connect to a WPA-secured Wi-Fi network, we need to create and populate the /etc/wpa_supplicant.conf configuration file.

Linux comes with a utility that generates the configuration for you: wpa_passphrase. To test it out, simply run wpa_passphrase <SSID>, where instead of <SSID>, you need to type in the SSID (name) of your Wi-Fi network surrounded by quotes. For instance, my Wi-Fi network at home is called Dumbledore, so this is what I type in instead of <SSID>.

When you press Enter, the utility will say # reading passphrase from stdin and it will wait for you to type in the passphrase for the network. Type in the passphrase and press Enter. After a few seconds, the utility will spit out the configuration text:

network={
   ssid="Dumbledore"
   #psk="01234567"
   psk=82e6ade8f8319c3a737e89ee125a58178073d66613c9a3af8fb6e7f5e04e1aa7
}

We want this configuration text placed inside /etc/wpa_supplicant.conf. To that end, we run the command again but we modify it slightly:

wpa_passphrase <SSID> > /etc/wpa_supplicant.conf

Remember to replace <SSID> with the name of your Wi-Fi network (surrounded by quotes; for example, at home I use wpa_passphrase "Dumbledore" > /etc/wpa_supplicant.conf). We have used the > redirection operator, an extremely powerful feature of the Linux shell. Basically, what > says is to take the output of the preceding command and place it in the file specified after it (overwriting it in the process). The text # reading passphrase from stdin is also placed in the file; so, when you run the command, you will see nothing, but the lack of the prompt (root@EV3:~#) will indicate that the utility is running, and is in fact waiting for you to enter the passphrase. Type in the passphrase and press Enter. After a few seconds, the prompt will reappear.

To confirm that it worked, run cat /etc/wpa_supplicant.conf. This will print the contents of the file:

# reading passphrase from sdtin
network={
   ssid="Dumbledore"
   #psk="01234567"
   psk=82e6ade8f8319c3a737e89ee125a58178073d66613c9a3af8fb6e7f5e04e1aa7
}

The lines preceded by a # are comments and are ignored by EV3 when setting up the Wi-Fi network. This simple configuration tells EV3 which network to connect to and what security key to use to connect to it.

Simply disconnect EV3 from your computer and restart it. It will automatically connect to the specified Wi-Fi network. The one I have at home hands out IP addresses in the 192.168.1.x range, and my EV3 was given an IP address of 192.168.1.14, which it proudly displays on the home screen (under the 10.0.1.1 address it uses for USB and Bluetooth networks).

To SSH into EV3 over the Wi-Fi network, run ssh root@<wifi ip address> (in my case, I ran ssh [email protected]). You can construct a new block in the ssh config file to connect using the IP address over Wi-Fi.

It is clear that the technique for setting up Wi-Fi connectivity on EV3 is rather painless. For those of you who would rather modify the SD card directly on your computer, plug in your SD card and create the /etc/wpa_supplicant.conf file. You can run the wpa_passphrase command on your Linux computer and place its output in the file. Now restart EV3 and it will work just as well.