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463 points bookofjoe | 5 comments | | HN request time: 0.576s | source
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er0k ◴[] No.45130518[source]
This is nothing new. Wifi signals have been used to detect objects, people and animals, gait analysis[1], read keystrokes[2], monitor breathing and heart rates[3], "hear" conversations[4], etc for at least a decade now.

https://news.ycombinator.com/item?id=12353605

https://www.theatlantic.com/technology/archive/2016/08/wi-fi...

https://archive.is/XnHUV

1: https://ieeexplore.ieee.org/document/7457075

2: https://dl.acm.org/doi/10.1145/2789168.2790109

3: https://archive.is/mFSDq

4: https://archive.is/sNVcM

replies(3): >>45131162 #>>45131394 #>>45131689 #
1. Uehreka ◴[] No.45131689[source]
Have you gotten any of these to work? A few years ago I was tasked with investigating these kinds of techniques for a client (it was something cool and benign but I can’t say what due to NDA) and the big papers people are referring to when they mention this all had either huge asterisks or huge methodological flaws.
replies(4): >>45131795 #>>45132026 #>>45133969 #>>45134006 #
2. ACCount37 ◴[] No.45131795[source]
Getting it to sort-of-work is fairly easy. Getting it to work well on off-the-shelf hardware without a precisely controlled environment is hell.

For practical applications right now, you'd want a dedicated radar unit at 24GHz or so, probably with two separate reception paths too.

Eventually, we might get usable radar functionality in default Wi-Fi chips with 5GHz/6GHz Wi-Fi and MIMO - but it's not there yet.

3. IshKebab ◴[] No.45132026[source]
In my experience aallll of these fancy "we can measure things that sound impossible" papers come with the asterisk "in perfect lab conditions".

> “The signal is very sensitive to the environment, so we have to select the right filters to remove all the unnecessary noise,” Bhatia said.

AKA "it barely works and we had to filter the signal to the gills to get anything at all".

It's a really impressive tech demo but the article is selling it as if this might actually work in the real world and it clearly won't.

4. genewitch ◴[] No.45133969[source]
i get asked about stuff like this from time to time and i always say "no, that's impossible" because i have ethics. The common retort is "well, i heard it was being used at <x>." and a client never contacting me again, which is fine.
5. antoniuschan99 ◴[] No.45134006[source]
Try using this you just need an esp32 devkit nodemcu style pcb. It measures movement though.

https://github.com/espressif/esp-csi