Cheap Cell-Phone Detector 296
An anonymous reader contributes a link to a BBC News article on a cheap cell-phone detector created by six New Zealand high-school students for a business competition, excerpting "The detector, which they have called CellTrac-r, works by picking up the bursts of radio frequency activity that emit from a mobile each time it sends or receives a call or a text message. The device can detect these bursts of electro-magnetic energy up to a radius of 30 metres. It can also measure the amount of the energy to determine the distance of the mobile.", and noting "Seems like a perfect /.er hack project, and as initiator I get 5% of gross profits."
Already have one (Score:5, Informative)
dicky-dick-dicky-dick-dicky-diiiiiick
Also useful for knowing when Im about to get a call and can start looking for my phone well in advance before it starts ringing.
Re:Tracking down specific people (Score:3, Informative)
And ofcourse, you need to beable to send this kinda stuff, I've seen it reported that IM services keep limited logs of IP's that use that.
Besides, if your gonna stalk someone, and be within 30 meters, AND have an active connection to Yahoo, you'd beable to use better ways to locate the person then a radio ping which may or may not work based on how crowded the area is.
just dosn't seem like a good method based on the way it works.
Simple explanation on directionfinding by radio (Score:5, Informative)
I often make the mistake of assuming people know what I know... in this cause, how most modern ADF (Automatic Direction Finding) equipment work in aircraft... Mea culpa =)
A coiled antenna - also know as a directionloop - recives the signal strongest when the 'open end' of the coil points towards the transmitter. If you have two coiled antennas, one orientated dead ahead (in relation to you) and the other pointing left-right (ie: being 90 degrees apart), it is reasonable easy to use the difference in signal strenght to figure out the direction the source of the radiotransmitter - in this case the mobile phone.
Three points (or antennas) would be needed if you want a fix on the radiotransmitter (mobile phone) and not just the direction.
I remember (Score:3, Informative)
Re:Neat, Now if only (Score:3, Informative)
Also, this device these kids are touting is nothing new. A google search will reveal various circuits schematics for cell phone detectors.
Re:Neat, Now if only (Score:3, Informative)
Jammers violate FCC regulations (Score:3, Informative)