Building a Device to Count People Using Cellphone Signal Detection and Triangulation

Is it possible to buy or build a device that will detect cellphone signals (ideally including signal strength) and then relay that information to a central location e.g. a web service? This could be used for the following purposes:
1. detect when a cellphone comes within range as a way of detecting the number of people going past a point.
2. set up a number of these devices in known locations to then use triangulation to detect cellphone locations
3. set up a database of cellphone identifiers mapped to people so that the location of people is known.

The device would need to comply with relevant laws since it would be operating in licensed radio spectrum but by a person not holding a licence. Perhaps that means it could only receive and would not be able to transmit any signal on the relevant cellphone frequencies. So it has some of the functions of a cell tower but that can be operated by anyone, not just a licensed cellular operator.

Any advice appreciated.

It sounds like your trying to build/buy a zone dector that has a built-in gps. You can buy it online from ebay they normally run $500.

im sure there are off the shelf products available but if you want to go building one yourself you could build a software defined radio(or buy one) and make it receive gsm packets, i think you can identify cell phones without actually decrypting the packages, this alone would allow you to count cell phones operating in the area, but if you want location data you would have to also do phase shift defined direction finding from several locations. as long as you dont transmit anything you dont have to have any licences. mind you this solution would not be a trivial project to undertake

Thanks. Can you give me a bit more information about the zone detectors? What would I search for? I've seen some that detect motion for a home alarm. I've seen plenty of GSM/RF detectors. However I can't find anything that will detect GSM/cellphone signals and relay that data on somewhere else.

It is possible to count mobile phones that have enabled bluetooth.
But this will be like 10 from 100. For statistics it is enough, but for preciose counting - not.

Better to use SensMax to count people:

SensMax is a manufacturer of people counting solutions that provides automatic people counting using
wireless people counters

The only real method of ever being able to do this is to interrogate the nearest cell site and then use triangulation based on three sites This would mean a direct link into the cellphone sites via PC acquisition

That would be the only way you could do this so as to pin point a persons position

The second is to ask the user by agreement to use tracking via GPS navigation Not everyone wants this and so you are back to square one again


You then would be able to set up a database constantly updated knowing the persons positions

However your going to come a cropper here with this as everyone knows that the best way to communicate secretly without you knowing, is to use infra red so your all the way back to square one again

Since infra red is difficult to detect

Secondly all they have to do is encode transmissions so as to make decryption almost impossible which can be done via rolling code or random sudo encoding

You actually have no real way of detecting cell phones disable the transmitter parts and your left with a highly useful peace of equipment that can be used to communicate privately and re main undetected even trigger various devices again without you knowing

So cell phone counters although marketed as highly suitable aren't really the ideal answer they never really work satisfactorily

Bluetooth is fine but then you have to enure Bluetooth is enable however this is prown to security problems one of which is they can interrogate the phone which they can do via RF anyway using gsm commands and obtain various information within your phone inclusive address books files etc etc

So that from a security point of view will not allowed Any engineer will tel you this who knows what he is doing especially with cell phones easy to hack into

Back to square one again

Last but not least you have the option of downloading software which enables GSM tracking and so on but again as anyone who knows what they are doing will tell you , they don't download software because they know full well that this then leaves the phone open to attack or to hacking exposing your private messages and of courses any other information that you may have

Back to square one again

Finally there is then the problem of the airtime providers etc who will not like this plus of cores our ever so concerned pop stars who have recently had their phones compromised and who think they are a little bit special especially the ones that support freedom fighters ho ho

These persons will then having discovered that you intend to do this will purposely start up their own broadcasts to interfere with your counting mechanism which will be useless under these circumstances so

Back to square one again

Yes Id give up on this idea if I was you wasting your time