I've looked at the other questions with similar titles, and they are asking something different to me. Please read the issue before marking it as a duplicate as I have a particular use case in mind which others have not asked as far as I am aware.
First of all please note that I am talking about using a rooted Android device and I am NOT talking about routers or access points signal strength.
Say there are five wifi networks in a location and you know there is a wifi device in the vicinity, but you don't know what wifi network the device is connected to. Would it be possible to detect the signal strength of some random wifi device (let's say a mobile phone to make things easy)?
I'm talking about making a spectrum analyser (or a software defined radio application) for the 2.4Ghz and 5Ghz frequency ranges, but I'm unsure of how to proceed. Since the device will be rooted, I'll be able to access the low-level APIs that the Linux kernel offers but I don't have much experience in this area.
