Mapping a Wi-Fi Network? 31
NivekEnterprises asks: "At my school where I am an Electrical Engineering major A Wi-Fi network has been set up, and is running in several buildings. Since the coverage extends outside several of my friends and I are trying to map the signal strength. Basically we are going to take a map of campus and walk around with a Wi-Fi enabled laptop, marking as best we can. Is there an easier way to do this? Has anyone else done something similar and is willing to share some their insights?"
Well... (Score:5, Informative)
Re:Well... (Score:1)
Re:Well... (Score:3, Informative)
Re:Well... (Score:2)
Plus, I want to be able to use maps in diff. countries I travel to...
Re:Well... (Score:2)
If you want to do this right I suggest you use kismet, a GPS receiver hooked up to the laptop, and use the most common configuration of wifi card. Don't use anything to boost the signal, assume that if someone can use an antena, they don't need you maps. Or make two sets of maps. Then set out with the data kismet collected and make a map. It's really easy to do this. GPS drive can help you with parts of it but it's not going to be entirely effective.
This has been done... (Score:3)
Consult google:
google [google.com]
GPS (Score:1)
The program will show you what spots are hot, what is not... Good luck!
Hmmm (Score:4, Insightful)
I'm confused .. (Score:1)
Re:I'm confused .. (Score:1)
GPS (Score:1)
Wireless InSite (Score:5, Insightful)
There are several methods by which this could be accomplished.
The first is to create a link budget using the two-ray approximation [earthlink.net] (1/R^4 attenuation) and the estimated antenna patterns. This allows one to bound the maximum range as a function of antenna orientation and receiver sensitivity. Most likely this is the analysis that was done when installing the network.
A second and much more enjoyable way is to use a ray-trace simulation program such as Wireless InSite [remcominc.com] to model your campus. This model will pick up multipath effects and folliage losses.
The most time consuming but most accurate method is to walk around with an antenna, measuring the power as one goes. It should be noted that when one measures in a given location the power will change over time sometimes quickly. Known as Rayleigh fading, it is due to time-varying multipath from a dynamic environment.
I recommend tracking down a communications professor in EE and borowing their copy of Wireless InSite. If you pitch it right you could even get a credit of independent study from it.
Michael. [michael-forman.com]
suggestion (Score:2)
Kismet (Score:5, Informative)
Re:Kismet (Score:3, Informative)
I'll also add a plug for GPSDrive [kraftvoll.at], which can run alongside Kismet and display your position "live" on a variety of different maps...
It also displays the position of the AP's as estimated by the running copy of Kismet.
gpsd + kismet on linux (Score:2, Informative)
Post the location and the SSID (Score:4, Funny)
Forget the map (Score:5, Funny)
Forget the map. What you need to do is find a way to get an analog signal strength reading (either with a device designed for the job, or hacking something on a laptop to (say) pipe a running digital signal strength value out the dsp to the earphone jack) and run it into an op-amp setup that will 1) give you decent current and 2) give you an inverted signal as well. Run these two signals to two actuators. Hook the inverted one to a can of red spray paint,and the un-inverted one to a can of blue spray pant.
Do this with the power off.
Go outside, make sure the cans are facing away from you, power up, and walk around.
From then on, the parts of campus with a blue tinge will be the ones with good signal, and the red areas will be the ones to avoid. Easy rule to learn, and no maps to deal with.
-- MarkusQ
P.S. You may need to go over some parts of campus (esp. plants, artwork, etc. that may be strongly coloured) with a coat of gray primer first. I suggest you just play around with it till you get something usable.
Check out Ekahau Site Survey (Score:1)
A Finnish company called Ekahau has a product called Site Survey that does map a wireless network visually and quite nicely, I might add.
We're currently planning a Wi-Fi network for our school as a final project and Site Survey seems to be a nice tool for figuring out the best places to set up APs so we get maximum coverage.
The Site Survey product can be found here [ekahau.com]
Too bad it's windows only...AND costs a bundle ( starting at $1995 afaik )
footwork (Score:1)
We tried a few different approaches. It turned out that the fastest approach was to send someone around with wireless card tools that showed SNR (signal to noise ration). In offices, the SNR at the most likely use location (e.g. the desk) for the "best" AP (access point) was measured. In classrooms, they broke big rooms into smaller chunks, then found the best SNR for each chunk.
An approach using GPS was tried, but it took longer to wait for the GPS to stabalize
build a bot (Score:2)
Without going outside? (Score:2)
Well, you can still do that, but here's what I would do before going outdoors, and this may even provide the level of accuracy you need.
First, make a digital map of your school. As simple as scanning/cleaning up a paper map given to new students, or snag one from your local city hall's zoning department (of course, doing that may end you up on an FBI watch list).
If you really want to geek out, grab a friend and hav
GPS is best... (Score:2)
Every ~25 seconds, laptop records WiFi signal strengths and network names and such to record #N, and emits a pair of tones corresponding to the last digit of N (I used musical intervals and the first tone was always the same; for the zero digit, the second note of the pair was null---in other words, a single tone). I carried a clipboard, which I would number as I went along, and fill in my approximate location. I could make
Just like phones... (Score:1)
if you have a mac (or access to one) (Score:1)
http://www.binaervarianz.de/projekte/programmie