How to capture raw signal from wireless router?

Question

I have seen several projects now which derive novel spatial information from radio data collected from a typical wireless router:

http://wisee.cs.washington.edu/

http://www.extremetech.com/extreme/133936-using-wifi-to-see-through-walls

The idea of using a wireless router as a sort of passive radar is fantastic.

I am very interested in experimenting with data collected from a wireless router myself, but there is little information on how to go about actually interfacing with a wireless router and getting a raw stream of information collected by the device. Similar questions have been asked on here before, but I am yet to see a satisfactory answer.

I don't have the rep points necessary to link to the other questions but see:

'Capture Raw Signal from WiFi card as You Would a Sound Card'

'raw wifi “signal data” access'

I am looking for a solution that would let me use a low-cost device such as the oh so common WRT54G wireless router. If your answer involves custom radio hardware, you needn't bother posting.

Answer 1

As far as I know, the only option using a commodity hardware is to use Intel 5300 Wifi card. You can get the complex CSI (amplitude and phase info therein) from the three antenna on it from a sample of subcarriers (OFDM). You can take a look at this site:

http://dhalperi.github.io/linux-80211n-csitool/