[trehanab]

I'm looking to count or detect how many people are walking through an area, and I wanted to know if this is possible using cellphones? Is there some kind of device I can make or buy (cost is not a major issue unless I have to build something in the range of a whole tower) that can ping the phones in a given radius of a few feet? I can increment a counter in software once I can detect the presence.

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› See More: cell phone count method?

[tavenger5]

Sounds like a complicated way to do a simple thing. I haven't looked but I doubt there is a consumer device out there that can do what you want. It would either have to pick up on the wireless signal itself, and take CDMA and GSM bands into account, or GPS/Bluetooth signal, which would only pick up people with that have that feature enabled on their phone.

Any way to get an overhead shot of the area? Then you could just take pictures at different times of the day to get a sample.

[trehanab]

It is a complicated way but certain factors would make this a really good way to count people in my particular situation ... i guess i'm a masochist like that. Plus I need an automated count system since its a high-traffic area, and I've been having trouble using camera counting technologies that are only able to work under certain conditions.

Now when you say pick up the wireless signal ... you mean I'd have to create a device to fool the phone into thinking its talking to a genuine tower? Sounds like I'd have to go to each individual phone company and beg them to let me have access to corporate licenses to allow me to communicate with their phones.

I have tried bluetooth scans but it turns out that only about 5% of cell phone users have their devices in bluetooth "on" and "discoverable" mode which was the only way I could find them. Unless there's a way to find them without 'discoverable' on.

[tavenger5]

It is a complicated way but certain factors would make this a really good way to count people in my particular situation ... i guess i'm a masochist like that. Plus I need an automated count system since its a high-traffic area, and I've been having trouble using camera counting technologies that are only able to work under certain conditions.

What is the area? Are you doing a study?

Now when you say pick up the wireless signal ... you mean I'd have to create a device to fool the phone into thinking its talking to a genuine tower? Sounds like I'd have to go to each individual phone company and beg them to let me have access to corporate licenses to allow me to communicate with their phones.

I'm no expert on cell phone towers, but I think what you would need is something that could pick up specific wireless 'pings'. In other words, cell phones looking for a signal. They do this constantly on specific frequencies. (GSM and CDMA) You wouldn't have to retransmit the signal, only know that it's there, and count it.

Here's a very simple version of what you would need:
Wireless Frequency counter

I have tried bluetooth scans but it turns out that only about 5% of cell phone users have their devices in bluetooth "on" and "discoverable" mode which was the only way I could find them. Unless there's a way to find them without 'discoverable' on.

Yeh, bluetooth probably wouldn't be as effective. You can't know that it's there in less it's enabled. GPS may have a higher 'on' rate since it is used for 911. But you'd probably be better off using the actual wireless signal since the 911 GPS signal is a little more protected. If just anyone could access it, then you could potentially know where anyone is at any given time.

[tavenger5]

This is interesting:

BBC NEWS | Technology | Schoolboys create mobile seeker

[trehanab]

Wow, this actually sounds quite promising ... thank you very much tavanger.

This is actually for a project. I have a queue, much like you would have at a theme park ride, for which I need to find out how many people are in line. There are many different ways to do so ... video sensors, thermal imaging, sonar, IR, phot-cell counters ... but these all have a large error rate in certain situations ... namely ... say a group of 100 school kids rushes through in a large crowd with barely any shoulder-shoulder room.

I was trying to think outside the box, and thought everyone has a cell phone, if I can just figure out how many cell phones are going through the line, i'd be golden ... i realize through more research that this was being a little too optimistic perhaps but your links have given me a great platform to build on. I might just try to create a frequency detector that reads a device within a few feet ... just the existence of one ... and try to use it as an end of line device.

Thanks again!

[trehanab]

ahh ... damn it i mis*****ed your name!