Yes, I'm aware of that solution. 3-5 meters isn't that much more fine grained than 15-20ft.

The difference being, I was talking about only using signal strength, and more importantly, using an unmanaged network. Cisco's solution requires a managed network, and it uses more than just signal strength. It also does time-of-flight. I've used those solutions too, but those also require special drivers on the client side. In the end, it still doesn't gain you much for the extra effort. 3-5 meters is still about 10-15ft

This is fine for determining what department of the store you are in, but it won't tell you what specific product you are looking at, or who is standing immediately next to you.

triangulating by signal strength is not that accurate. Especially if you don't know what the Tx power was. I've gotten about 20ft accuracy in practice with many APs in range. Good enough to know you are in the frozen foods section of the grocery store, but not good enough to know who is standing next to whom at the frozen foods section.

I wasn't arguing that you can't. I was responding to an earlier poster that was paranoid about being able to tell proximity with other users, so that they could tell that you were "with" someone. In that scenario, your position inside the gym is extremely important.

That's not true at all. I've only found that to be true if I'm testing inside a faraday cage inside a controlled lab. Your signal strength will vary depending on what is between you and the AP, so if the people around you are different everyday, your readings will be varied. Even if those were constrained, your signal strength will vary depending on humidity and signal population density. You can probably get a nice average, if I monitor the data for 10 days. But if you are only inside starbucks for 10 minutes/day to grab a coffee, that is not enough time to build out something like that.

It's not as easy as you think. I spent a long time researching this, and I had a Mathematics PHd on staff helping me. I was able to get granularity down to about 15-20ft, when I saw about 20 access points. But 15-20 ft is still pretty big if you are trying to get spatial orientation between people...

And even then, even when I saw 20+ AP, I was still able to find points inside our building where I got matching signal-strength profiles from the APs as another location pretty far away. Remember, proximity detections is not the same as location tracking. I can get unique profiles from contiguous location blocks, but I can't guarantee the same for non-contiguous blocks.

True, it's a single command. However, that command only works if the the chipset supports that feature, and if the driver supports going into that mode. Neither of these are true on all the phones I've tested.

They are looking at the beacon packets your device is sending out when it does a scan of the network. Most OS's will do a periodic passive scan to look for networks.

You're talking about being connected to a hotspot. Euclid is talking about detecting your MAC when you *are not connected* to any network, by monitoring beacon packets.

Not really. I go to the gym everyday at the same time, and I see the same people there everyday... That is a coincidence that we have similar schedules... I am not in a relationship with any of those people I see regularly.

I have a set routine of what I do at the gym, as do most of the regulars I see regularly. For example, I may start on one side of the gym, and work my way to the other, and someone else may start at the opposite end, and work their way forward. It is entirely possible for both of us to maintain the same signal strength to the AP the entire time in relation to each other, simply because we are on opposite sides. There's no way to draw any conclusions from this data, other than we're both inside. You can try to write an app to figure out that we were standing next to each other the entire time, but that is a VERY complex problem to solve, and you aren't going to solve it by simply monitoring beacon packets.

Not that it matters, but it doesn't work that way... (My full time job involved researching proximity algorithms)... Using Wifi as proximity, you can tell that say these 5 particular people are in a room, but you have zero idea the spatial relation of each of these 5 people to each other, without the aid of other sensors. Wifi or bluetooth will not give you spatial relationships in any meaningful manner.

For example, if my signal strength to the AP is 80%, and your's is 80%, that does not mean we are next to each other. We can be on opposite sides of the AP, or we can be at some other arbitrary location, where each of us has a different obstacle blocking the direct line of site to the AP, reducing the signal strength by differing amounts. Plus we have no idea what the transmit power is on each device.

You may be able to get a reasonable guesstimate of proximity to the AP, but not spatial orientation to the AP. (ie, you are within 20 ft of the AP, but you don't know in which direction), and certainly not between each peer. The phone will not be able to give you proximity information to another phone using wifi, because the stock chipset on Android and iOS does not give you access to read these beacon packets from arbitrary un-connected devices. I've been able to get it to work in the lab, but only when I use specific hardware/chipsets, with special drivers/firmware.

So all I'm saying is that people are making this to be a bigger deal than it is.

Maybe I'll write an app that will flood the airwaves with ping packets, using a random MAC in every ping... Then I can vary the Tx power of each ping, so that their signal strength reading will be out of whack too. So they'll get thousands of unique hits, with signal strength readings all over the map.... (My last project was reading/writing these broadcast packets, so I know how to spoof everything in the packet... evil grin...)

If that's the case, it makes me wonder if any licensing terms of the software was violated. Using tools that is licensed for corporate use, for personal use, is a violation of most licensing terms I've seen... For example, if MSFT licenses Office for your work to use, you technically can't use those licenses to run a copy of it at home. I wonder if the principal would have standing by arguing that the spyware was not properly licensed, thus any evidence obtained with it is invalid.

Yes, I was speaking to AT&T... But, no, that is still HTC's fault... Samsung didn't succumb to AT&T's desires to lock the bootloader. HTC did tho. My guess is that was part of the deal for carrier exclusivity I suppose, but I don't think HTC is doing themselves any favors by locking that phone into a single carrier, and then locking it down so that geeks won't recommend it to their friends...

exactly! I had HTC phones before and loved them, and recommended them to all my friends. I currently have an HTC One X... While I like the phone, the hoops I had to jump through to unlock the bootloader was crazy. And if I ever have to replace my phone, it will most likely come with the updated ROM and hBOOT so that you can't unlock the bootloader. (You have to root first to be able to unlock bootloader. The OTA doesn't have a root exploit, so unless you already unlocked the bootloader, you can't root. So now I am certain that if this phone ever goes kaput, my next phone will be a Samsung, unless the Nexus 4 has LTE, which I heard doesn't... So now I push Samsung with all my friends, instead of HTC. So as a result, a bunch of my friends have Samsung phones now.

I used to think the same thing when I first came out of college... But actually use math quite a bit in my current job. (Software Architect in a research lab) I use Linear Algebra (which for me, in college comes after Calculus 3), as well as Calculus. You probably will too if you say you want to go into gaming, particularly when you start looking into sensor input. I'm not doing gaming, but I'm looking at sensor input, for things like gesture tracking/recognition, sound analysis, as well as more basic things like looking at accelerometers and magnetometers. I didn't really use Number Theory directly, (graduate course for me, and I flippin' hated that class), but we do have a Math PHd on staff, and I did have to consult with him a number of times.