I'm having a Yun setup for sensor data collecting . I log in over 3G to learn how
or if there are wifi networks available. I would like to see the signal strength of any
wifi available in the arduino Yun config page. Is this possible ?
I don't know if this is a good answer but you can both go in the advanced config panel (the OpenWRT luci original panel) or use the /usr/bin/pretty-wifi-info.lua script inside the linux side.
While I second mantissa00 suggestion, your feature request makes sense, bartdereu: please open an issue on Issues · arduino/YunWebUI · GitHub requesting the additional info to be displayed
-Sorry for this late answer-
I know that i can see wifi signal strength in de Luci control panel , but then you have to be connected
to that wifi network to see the signal.
Here's the deal :
we log in on the arduino trough 3G (a dongle), scan for available wifi networks and connect to the strongest;
If i don't see their signal strengths i have to connect to them all to see it.
I'm working on the issue posted by mantissa00 See Wifi Signal strength in the config panel. · Issue #16 · arduino/YunWebUI · GitHub
I tried the solution that Federico offered.
opkg update
opkg upgrade luci-app-arduino-webpanel
but no changes are seen on the webpanel ? (i rebooted the Yun just in case)
Can you paste the output of this command
opkg list-installed | grep webpanel
gives me :
root@Arduino:~# opkg list-installed | grep webpanel
luci-app-arduino-webpanel - 1.5.2-1
root@Arduino:~#
and this is the webpanel :
That is super strange. Can you help with debugging? Please log into your yun via ssh, the type
lua
This should show this prompt
Lua 5.1.4 Copyright (C) 1994-2008 Lua.org, PUC-Rio (double int32)
>
Now type
sys = require("luci.sys")
iw = sys.wifi.getiwinfo("radio0")
util = require("luci.util")
wifis = iw.scanlist
= util.dumptable(wifis)
= "done"
Finally, please copy paste the output here.
Ofcourse i'm willing to help 
the output :
> wifis=iw.scanlist
> util.dumptable(wifis)
1 table: 0x4d7398
encryption table: 0x4d6270
enabled false
auth_algs table: 0x4cd410
description None
wep false
auth_suites table: 0x4bfd00
wpa 0
pair_ciphers table: 0x4d60e8
group_ciphers table: 0x4e6940
quality_max 70
ssid USR8054
channel 7
signal -36
bssid 00:17:3F:3E:51:4A
mode Master
quality 70
Keeps on being super strange. It looks like you are still using the old code.
Since we just released version 1.5.1, do you mind upgrading and see if things get better?
Otherwise another quick try can be typing
opkg update
opkg install --force-reinstall luci-app-arduino-webpanel
This is what i get :
root@Arduino:~# opkg update
Downloading http://downloads.arduino.cc/openwrtyun/1/packages/Packages.gz.
Updated list of available packages in /var/opkg-lists/attitude_adjustment.
Downloading http://downloads.arduino.cc/openwrtyun/1/packages/Packages.sig.
Signature check passed.
root@Arduino:~# opkg install --force-reinstall luci-app-arduino-webpanel
Removing package luci-app-arduino-webpanel from root...
Installing luci-app-arduino-webpanel (1.5.2-1) to root...
Downloading http://downloads.arduino.cc/openwrtyun/1/packages/luci-app-arduino-webpanel_1.5.2-1_ar71xx.ipk.
Collected errors:
* opkg_install_pkg: Package luci-app-arduino-webpanel md5sum mismatch. Either the opkg or the package index are corrupt. Try 'opkg update'.
* opkg_install_cmd: Cannot install package luci-app-arduino-webpanel.
root@Arduino:~#
webpanel is completely gone now too 
I've just retried, after having reflashed the latest image (1.5.1), and here is the output
root@Arduino:~# opkg update
Downloading http://downloads.arduino.cc/openwrtyun/1/packages/Packages.gz.
Updated list of available packages in /var/opkg-lists/attitude_adjustment.
Downloading http://downloads.arduino.cc/openwrtyun/1/packages/Packages.sig.
Signature check passed.
root@Arduino:~# opkg install --force-reinstall luci-app-arduino-webpanel
Removing package luci-app-arduino-webpanel from root...
Installing luci-app-arduino-webpanel (1.5.2-1) to root...
Downloading http://downloads.arduino.cc/openwrtyun/1/packages/luci-app-arduino-webpanel_1.5.2-1_ar71xx.ipk.
Configuring luci-app-arduino-webpanel.
root@Arduino:~#
Ok, i did the reset to 1.5.1 and then this force re-install. Works as expected now, thanx allot !
will it be needed in the future to have to do this force reinstall ?
It's actually already included into 1.5.1
Hmm, strange, because i tested it when i had it reset, but it was only active after i had force-reinstalled trough SSH