Detect 2.4ghz RF Disruption, then rx/tx reports in network?

Discussion in 'General Electronics Chat' started by gofightisis, Aug 16, 2015.

  1. gofightisis

    Thread Starter New Member

    Aug 16, 2015
    Electronics is not my field, and I'm not planning to build this, but was hoping here that I can spark some interest so that I can know if it is just fantasy. To me, this seems simple.

    It concerns the technology in the following article, which is readily found with an internet search -

    "Radio Communication Protocols in a History Aware Device-Free Passive (DfP) Localization." By Gabriel Deak, Kevin Curran, and Joan Condell

    Reading the article, I begin to wonder how plausible it would be to use off-the-shelf 2.4 ghz tech, to detect disruptions to it's field. Then to transmit that detection with it's own identifier, and a time-stamp on the same frequency to others in a network to form a connected web. And so each would tx/rx to detect a body in its field, then report, and relay the reports of others in the network. The network could be monitored at the field of any detector in the array. And all information would be the same at each detector. Each detector would simply broadcast its report regularly, consisting of a rolling log of all events received from each detector in the network. Less than 100 characters per device I presume. This would effectively free up the design proposed in the article, by doing away with the author's supplemental and redundant wireless communications.

    In Viet Nam, we dropped devices in the forest that transmitted alerts when the ammonia of urine was detected. With monitoring, these were able to determine troop movements. I'm wondering along these same lines.

    Critical would be the actual sensitivity and distance that a 2.4ghz device could reliably detect a human or animal. Also critical is the ability for these devices to communicate logically. And since 2.4ghz wireless house phones rx/tx all kinds of logical data, I assume these the logical choice for this. So some code would need to be written somewhere, that tells something to do something. My expert opinion.

    How to monitor and detect is beyond me also. These folks in the article mention using a “Received Signal Strength Indicator” RSSI in IEEE 802.11 to detect disruptions to the field. I imagine it is simply a software detection and display method. But I honestly don't know whether that is important except for the networking protocols they propose to put on a secondary system. Again, I propose eliminating the 802.11 system they mention because it seems redundant to an already tx/rx system. And honestly, a 2.4ghz house phone can handle the data I'm discussing, while outperforming most 802.11 wireless systems for distance.

    I'm imagining a few hundred house phones in 2.4ghz spread out over some acreage. Each with a wired alpha, beta, and gamma array of three pencil sized antenna. Camouflaged up in a tree with an out-of-sight, solar charged 6v battery. Each detector would TX and RX at just sufficient intervals to detect and send, while saving power.

    It would also be necessary to display the information being reported, and secure them with encryption. If something were wrong with a detector, the reports throughout the network would reliably reflect it like an electrocardiograph. And then I suppose a programmer would make such data even more readily digestible on a display, with alerts, and trends, etc. I'm also thinking that it would be very safe from hacks because the non-centralized, and non-linear form of communications means that even an effective hack of either one or all of the devices, would innately reflect somehow in the reporting system.

    And if this is all plausible, then how small, powerful, and far can these be taken? How much more accuracy and information can we get by overlapping the fields of several devices? Can we detect speed, elevation, height and weight? Is it properly theorized then, that a programmer could create a graphic map of movement and activity, with accurate numbers? Could it perhaps be refined and calibrated to distinguish somehow if the rf disrupting person had metal on their body? Could it then determine whether they were vocalizing, or even what they were saying? We are talking about phones afterall. I'm almost certain that someone out there would know of some Horst VonKuler who invented all of this in WWI. Regardless, I would still be interested in the idea.

    Can we have detectors throughout a forest or throughout a compound? Can swarm drones carry them over places where FLIR and other detecting technologies cannot penetrate? Creating a roving system of personless, person-detectors. Or maybe a hundred tarantula-size bots that can come in at night, set up an array in the trees, or buried in the dirt. Can this type of automated detection be used to automate other devices like lights, microphones and cameras, armaments, satellites, or an automated-human-subduing system?

    It sounds like such an rf disruption detecting system would be an unobtrusive, inexpensive way to accurately locate and track someone in the open.

    Realistic, or rf.jpg are there other critical factors I'm completely missing?
  2. #12


    Nov 30, 2010
    Could you re-phrase that in less than 500 words? If you do that, somebody who understands the limitations of your idea would be more likely to read your request.
  3. gofightisis

    Thread Starter New Member

    Aug 16, 2015


    the article I'm referencing is the invention that uses 2.4ghz rf to detect the presence of people, because the water in our bodies interferes with this frequency, and this is detectable. It then adds a wifi master to organize a number of these RF detectors into a network of people detectors. This is modeled in a home to detect intruders or injured people. I wonder at just getting rid of wifi and using the tx/rx of the detectors to communicate with each other and form a confederate network of autonomous detectors out of common off-the shelf technology.
    #12 likes this.