PiBox » pibox-network-config

https://www.cyberciti.biz/tips/linux-find-out-wireless-network-speed-signal-strength.html
I can use "watch -n 1 cat /proc/net/wireless" (or a thread based alternative) to monitor the wireless signal.

or to run through a popen(): cat /proc/net/wireless | tail -1 | sed 's/ \+/ /g'

http://www.howtogeek.com/197268/how-to-find-the-best-wi-fi-channel-for-your-router-on-any-operating-system/
I can use "sudo iwlist wlan0 scan | grep \(Channel" to find which channels are in use and recommend which one to use

http://www.linuxjournal.com/content/wi-fi-command-line
Noisy environment settings:

• sudo iwconfig wlan0 retry 16
• sudo iwconfig wlan0 frag 512
• sudo iwconfig wlan0 commit

According to this video the best wifi channels are 1, 6, and 11. I should scan the network for traffic on those channels and pick the best of those automatically. It also suggests more tx power can be used (if hostapd.conf permits) but will generate more heat.

Wireless API information is available from the Linux Wireless web site.

Overlapping channels come in sets, meaning if you can find channels that aren't in use and dont overlap those in use then that's the best channel to use for a WiFi network. Also there are really only 14 channels we care about for g @ 2.5GHz with four more added for 5Ghz.

Graphs could be straight edged or with an arc.

Selecting colors:

• http://devmag.org.za/2012/07/29/how-to-choose-colours-procedurally-algorithms/

Making progress. I've got a Cairo based display showing which channels are in use and by how many networks. Now I want to graph the signal strength. To do this I need to run this command:

$ iw dev wlan0 scan
BSS 10:6f:3f:e7:24:55(on wlp3s0) -- associated
    TSF: 797749164512 usec (9d, 05:35:49)
    freq: 5200
    beacon interval: 100 TUs
    capability: ESS Privacy (0x0011)
    signal: -62.00 dBm
    last seen: 82272 ms ago
    Information elements from Probe Response frame:
    SSID: MuseBA
    Supported rates: 6.0* 9.0 12.0* 18.0 24.0* 36.0 48.0 54.0 
    DS Parameter set: channel 40
...

So look for the BSS in the first colmn to find a new entry. Then parse out the signal strength, SSID and channel. That's good enough to start. I can graph the signal and show the SSID with each graph.

Here is how you convert dBm to a percentage. It assumes a maximum dBm of -50, which seems about right from my laptop.

quality = 2 * (dBm + 100)

Graphing of wifi channels and signal strength is complete. Code is committed and pushed. Looks pretty good, actually. I select colors for the graphics using the golden ratio.

Now I need to add all 14 channels to the options menu for selecting a channel for the access point. Then I should set the default to 1, 6 or 11.

Done. All changes committed and pushed.

Closing issue.