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Topic: RF signal Cellphone detector (long distance) (Read 290 times) previous topic - next topic



Is there a module that detects the rf signals of a cell phone over a long distance? Lets say 10 metres.
I want to make that rf signal distortion to trigger a action.


Your post makes little sense.
What do you mean by rf signal distortion.
In general the answer to the question is no .


Ok, I need some kind of sensor that detects when a 'active' cell phone is nearby.
The first thing i could think of was the output of the rf signal.


It takes a large box full of electronics to distinguish a cell phone from other signals.


A lot depends on a cell network in your country/region. For  standards operated in 460 / 900 MHz very easy, you need Si4432 module

Things may get tricky in 1800/1900 MHz .


as jremington says distinguishing a cell phone from other signals is difficult.   If you just want to trigger off the presence of a transmission at a particular frequency the you may find this helpful http://www.rtl-sdr.com/ depending on the frequency used for cell phones in your location.   However a cell-phone thats not on a call will only transmit briefly every 10-15 minutes making this not so useful for many applications.

I've noticed that if I leave my cellphone right next to an AM radio I can hear some interference when the phone checks in with its base station- whether this can be used to achieve your 10 metre range I dont know.

See also http://www.rtl-sdr.com/rtl-sdr-tutorial-analyzing-gsm-with-airprobe-and-wireshark/


Before starting a cell phone detection project you should review patents.  its a good thing to do a search of your project it will save you in the end
michael rosen akron ohio patent holder


Theres 2 primary types of cell phones standards.
GSM and UMTS which uses WCDMA.
A GSM phone is fairly easy to detect when it transmits as the transmission which is TDM sounds like a high frequency buzz, so as long as you know the phones frequency detecting it would be easy.
A WCDMA phone is far harder as the transmitted spectrum looks and sounds like broadband noise so most conventional detection methods wont work.

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