How do I pass signal strength info from a phone to a tethered tablet? I regularly tether my Wi-Fi Xoom to a Galaxy Nexus. In the interest of preserving the phone battery I normally leave the screen off, however this can be frustrating when the connection drops since the Xoom reports a full Wi-Fi signal regardless of the 3G connection's strength. 

Ideally what I want to do is replace the Wi-Fi signal strength symbol with the mobile's connection strength, however I'm anticipating it would have to be an extra icon in the "system tray" of the tethered device. 

I'm now going to speculate about how it would be done *: Wi-Fi explorer reports the Wi-Fi signal of the connected device, presumably by dynamically writing the system data to the HTML file it serves. Something similar, paired to an app that reported the results in the system tray/dock area would do it.



* I think this is still in scope since it might help with an answer. It isn't a coding question since I'd never be able to build this!
Here's a version I developed that does it exactly like this - be aware there could be bugs in this, it may not work for CDMA/EVO as am in the EU using GSM! 

It is a client/server based architecture. 

Install

To install the application, do the following:


Plug in cable into device
adb install WifiTether3G-release.apk


The gist of the app is this: 

Server

Activate the Wifi Tethering, then:


Launch this app - WifiTether3G
Hit menu
Tap on Settings
Set the app to either be a client or server.
If server, put in a name for the server - its a nickname, that can be anything you like. Default is *WifiTether3G_AP*. Likewise, set up the port, to be anything over 1024 and less than 65536 (Why? Internet reserves ports from 0-1023!) Default is 1337 ... :)


The above shall be for the server.

Client

Activate the Wifi to connect to the WiFi Access Point, then:


Launch this app - WifiTether3G
Hit menu
Tap on Settings
Un-check the box Server in order to make the application behave as client.


Tap on Start on the main application window, depending on which side is it - if it's server, it will run listening on the specified port.

If the application is running as client, it will connect to the server, and periodically waits for the incoming data and notifies the notification pull-down bar.

The message on the notification bar will be similar to "ServerNickname's 3G Signal is " followed by the following:


Crap - 1 bar signal
Alright - 2 bar signal
Good - 3 bar signal
Excellent - 4 bar signal


(Am not sure exactly how it would be for CDMA/EVO)

This will be followed by the date/time in square brackets for example, [05/09 19:33:01]

Edit:
I am in the process of updating the code, there's a widget in place but needs a bit more spit and polish... stay tuned :)

Update:

I have updated the application, there's a widget now in place, if running as a client, long press on home screen, pick WifiTether3G which takes up 1x1 space, the graphical image will change based on the signal. Also, for the settings screen, notification can be switched off as you wish. I will be uploading it to Google Play Store as a free app, shortly. (Linky updated) version