WIFI USABILITY

Reg Arvidson

Idea

Track signal variances throughout the day

Get a feel for the “usability” of a WiFi access point (or location)

Present this as a map to easily spot “lagging” areas

Implementation

Create a client program to collect WiFi/GPS data and submit to a server

Server catalogues data into a database while waiting to serve map requests

Clients can request a map from the server showing WiFi data for GPS points

High-Level Architectural View

GPS WiFi

Client Server

GPS/WiFi Data

Map!

If it was only that easy…

Client View (Data Collection)

GPS_Parser

COM_Access

WLAN_Access

GPS Serial Data

WiFi Signal Data

WiFiGPSDataUnit cURL Internet

Server View (Data Collection)

postdata.php

Apache Web Server

MySQL Database

Internet

Server View (Data Service)

index.php

Apache Web Server

MySQL Database

Internet

testdisp.php

kml.kml

Client View (Data Service)

Internet

Your favorite web browser!http://shyguy2.mine.nu

Or Google Earth…http://shyguy2.mine.nu/kml.kml

Data Collection

Flag a GPS fix if at least 3 satellites in view

Utilize fix data to time 5 second intervals If fix, poll WiFi interface for access points Tag SSID and signal strength to GPS fix If internet available, submit data, else

store for later! Runs in background, works even when

using any access point or the Internet

cURL Library

Created a URL to pass data to PHP script http://shyguy2.mine.nu/postdata.php?

datetime=1234&lon=-84.5675&lat=23.4326&ssid=UCF&sig=23...

cURL library allows easy usage of GET If GET fails then we leave data in buffer

and try again later

Data Buffering

A cURL failed GET leaves data in a buffer Allows roaming off the network, across

town, local pub, etc Upon reconnecting with friendly access

point will push data to server

Displaying Mapped Data

Going to homepage, index.php, triggers creation of KML file, kml.kml through use of testdisp.php, with all collected data from MySQL database

Automatically loads map using this freshly created KML file

Mapped data shows signal strength of SSID tagged to a GPS point, marker colors reflect signal strength

Can also load KML into Google Earth for a much more interactive view

Problems

Laptop Died Created new database Recovery of project files Rebuilt for new target machines Recollection of data

Lack of data (due to stated death)

Improvements

Can easily add additional data in minutes Security algorithm (if used), for example

Better data transfer method Direct connection to SQL server for

instance DATA DATA DATA DATA DATA

Questions?

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