Comment by transpute
4 years ago
It's also passive. Someone could stand outside your house or factory with their device and "illuminate" activity inside the building. Only EMF shielding in/on the walls could block them. Nation-state regulators could get involved, since these devices would be using spectrum that belongs to the public.
2012 article on a military use case, https://www.popsci.com/technology/article/2012-07/seeing-thr...
2017 video on an industrial use case, https://www.digitaltrends.com/cool-tech/wi-fi-radiation-tran...
This is very similar to radar, which raises the question, is radar already used to spy on peoples movements through walls?
X-Ray backscatter is definitely used for this, most famously by secret NYPD vans.
https://www.theatlantic.com/politics/archive/2015/10/the-nyp...
> The radars work like finely tuned motion detectors, using radio waves to zero in on movements as slight as human breathing from a distance of more than 50 feet. They can detect whether anyone is inside of a house, where they are and whether they are moving.
The cost of those devices should fall with 802.11bf Wi-Fi.
> the vans deliver a radiation dose 40 percent larger than delivered by a backscatter airport scanner; bystanders present when the van is in use are exposed to the radiation that the van emits… there may be significant health risks associated with the use of backscatter x-ray devices as these machines use ionizing radiation, a type of radiation long known to mutate DNA and cause cancer.
Could this radiation meter detect the presence of such a van?
https://www.gqelectronicsllc.com/comersus/store/comersus_vie...