PHP to obtain Wireless Signal Strength from Laptops

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krusaderx
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PHP to obtain Wireless Signal Strength from Laptops

Post by krusaderx »

Hi everyone, I'm new to PHP coding and I would appreciate it alot if I could get some help with something I'm working on.

First a bit of background before my question:

I'm working on an local area indoor location awareness system. It's something like GPS for the outdoors, but since GPS doesn't work well indoors (no direct line of sight from satellites) I'm planning to work with WLAN signal strength from WLAN access points to determine a user's location. How this works is roughly described as follows:

1. Let's take for example the ground floor layout of a building that has more than 3 WLAN access points. The floor layout is divided up into different smaller sections of roughly equal size and labeled A-Z respectively.

2. A database of WLAN signal strengths versus location is built by simply walking around the floor with a laptop, gathering average signal strength readings from some WLAN software, from location A to Z on the floor map.

3. After that, a user can walk around with a mobile device (presumably a laptop), and will be periodically updated of his current location by comparing the current signal strength, gathered by his laptop at any particular point in time as he is traveling through the local area, to the predetermined database of WLAN signal strengths.

The clinch is this: I plan to implement a web based application using PHP and MYSQL which any user with a browser and a WLAN enabled device without the need to run any external software. All the code needed to determine current location will be run off a central server.

My problem is this: Since I know that it is possible for a WLAN enabled laptop to detect and display signal strength on it's own (it can be natively shown on the taskbar without the need for external software), is it possible for me to obtain a numerical signal strength reading directly from my laptop? I'm assuming that it would be embedded within an operating system file that is native to the OS (or in general Windows). If yes, can PHP access and extract this data in numerical form (signal strength in dBm)?
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requinix
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Re: PHP to obtain Wireless Signal Strength from Laptops

Post by requinix »

krusaderx wrote:is it possible for me to obtain a numerical signal strength reading directly from my laptop?
Yes.
krusaderx wrote:If yes, can PHP access and extract this data in numerical form (signal strength in dBm)?
No.

PHP runs on the server, not on the client. All it knows is what the browser tells it, and last I checked they don't send wireless signal information over the internet.

You can probably do it with ActiveX and possibly with JScript. Even Flash may get you somewhere but I wouldn't bet on it.

My honest opinion? This isn't going to happen with PHP - at least not in any significant amount.
krusaderx
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Re: PHP to obtain Wireless Signal Strength from Laptops

Post by krusaderx »

Thanks alot tasairis... Really appreciate the heads up.

If you dont' mind going off a non-php related note then... Which is the system file that I will need to access to obtain the signal strength reading?
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requinix
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Re: PHP to obtain Wireless Signal Strength from Laptops

Post by requinix »

On Linux/Unix I don't know. On Windows you'd need an API call (search around MSDN to find out).
krusaderx
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Re: PHP to obtain Wireless Signal Strength from Laptops

Post by krusaderx »

I've been trying to find a external solution to my problem and this is what I've come up with:

I've found that Netstumbler (a WiFi sniffer) can output signal strength in numerical form onto a text file which will be stored on the client side. Is it possible to configure PHP on the server side to automatically detect and read this text file? Or if not, is there any other code that can do this?
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requinix
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Re: PHP to obtain Wireless Signal Strength from Laptops

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krusaderx wrote:Is it possible to configure PHP on the server side to automatically detect and read this text file?
No. You're basically asking if a server somewhere on the Internet can access some arbitrary file on a client's computer...
krusaderx wrote:Or if not, is there any other code that can do this?
Flash probably can.

But this path you're taking is not the best way to go. Just because it might work doesn't make it a good idea.
krusaderx
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Re: PHP to obtain Wireless Signal Strength from Laptops

Post by krusaderx »

Thanks alot for your answers tasairis, I really appreciate you taking the time to answer my questions. I'm thinking of changing the whole web based application implementation and building an actual program instead. Take care man.
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