Detect cell phones with Arduino?

I watched a video from the Make website about using Arduino to detect Electromagnetic fields and it got me wondering…

Would it be possible to use an arduino to detect when there is a cell phone within a certain distance, say 20 feet?

I appreciate any thoughts…

do u ahve a link to the article, this sounds interesting :slight_smile:

http://blog.makezine.com/archive/2009/05/making_the_arduino_emf_detector.html

well the method they use would inform u of an electrical device in your proximity, but even then the devices would have to be like a foot away… the guy on the vid pretty much touched the things he was testing with the probe, so 20 feet might be pushing it by a lot

do u know exactly what sort of signals are sent by cell phones? i could not find it on wiki or google…

Please look thru this circuit and interface it to arduino.
http://www.circuit-projects.com/rf-radio-frequency-circuits/cell-phone-detector.html