2016-08-18

WiFi on UBOS

/blog/2016/08/18/wifi/

Update: UBOS now has built-in WiFi support via the UBOS Staff and the manual setup described in this post should not be necessary any more.

Unfortunately, the state of WiFi on Linux in general is a mess. We can’t fix that general mess single-handedly on UBOS I’m afraid. But when your WiFi dongle has the “right” chip set, using WiFi on UBOS can be surprisingly easy. Such as when using Element14’s Wi-Pi (datasheet) with the Raspberry Pi.

Here is how I just set up WiFi for a Raspberry Pi that is installed in my back yard, where it controls the pumps of my pool, running UBOS of course (more about that project). I needed to replace the SD Card of that Raspberry Pi, and decided to do a clean reinstall.

Boot UBOS on your Raspberry Pi, and log in (either via console or via SSH over Ethernet)
Insert the Wi-Pi dongle into the USB port
Determine its interface name, by executing:
```
% ip link
```
In directory /etc/wpa_supplicant, become root by executing:
```
% sudo bash
```
and create a file called wpa_supplicant-wlan0.conf.

This assumes that the name of the WiFi interface you found with ip link above was wlan0. If it is something else, adjust the name of the file correspondingly. This file needs to have the following content:
```
ctrl_interface=/run/wpa_supplicant
eapol_version=1
ap_scan=1
fast_reauth=1

network={
  ssid="XXXXXX"
  psk="YYYYYY"
}
```
Replace XXXXXX with the name of your WiFi network you want to connect to, and YYYYYY with your WiFi password.
Set the correct regulatory domain. In directory /etc/conf.d, edit file wireless-regdom and remove the comment from the line that represents your country. For example, if you reside in the US, change line:
```
#WIRELESS_REGDOM="US"
```
to read as follows:
```
WIRELESS_REGDOM="US"
```

Start the Wifi daemon:

% sudo systemctl start wpa_supplicant@wlan0
% sudo systemctl enable wpa_supplicant@wlan0

Again, use the correct interface name.

You are done! You can check that you have an IP address with:

% ip addr

and you should be able to access any website you like, such as:

% curl -v http://ubos.net/

If it doesn’t work? Check that you got the right mix of underscores and hyphen in the file you created. And, of course, wpa_supplicant is known to only work with some WiFi adapters, not all. But IMHO spending a few dollars on an extra, supported WiFi adapter beats spending hours attempting to debug WiFi drivers. At least that’s what I did.

Updated 2016-11-14 with setting the correct regulatory domain.