WiFi signals can measure heart rate

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

[edit: publicly announced] commercial deployment into homes and offices is new.

Indeed, this same principle has been shown to work with sound waves and not just RF waves. There was a paper a few years back that used car speakers and the microphone to be able to detect the number of people in the car for the purpose of detecting children or pets left in hot vehicles.

Or is it?

Generally I think this is called "tomography" (https://en.m.wikipedia.org/wiki/Tomographic_reconstruction) i.e. the reconstruction of higher dimensional data from lower dimensional data. Your brain can do it automatically in a lot of cases. For example if you see the shadow of a rotating cube on the wall, your brain can reconstruct 3d information about the cube even though you only have access to a 2d projection

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.

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.

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.

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.

Try using this you just need an esp32 devkit nodemcu style pcb. It measures movement though.

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