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mmWave radar, you won't see it coming

joshhorne.com

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Re: mmWave radar, you won't see it coming

#21

Post by [deleted] »

hornej wrote: post #16
chrismorgan wrote: post #15

A technical error in one of the diagrams: Hall effect sensors are not binary, but one-dimensional, and are used so; their output voltage is directly proportional to the magnetic field strength. As for PIR sensors, fundamentally they’re certainly not binary, but I have no idea if they perhaps expose only a binary signal. A better example of a binary sensor might be an on/off switch.

thats a good point about the hall sensors. i'll update that. PIR sensors also output an analog signal, but in practice they are binary.

[deleted]

Re: mmWave radar, you won't see it coming

#22

Post by na85 »

jacknews wrote: post #14

"One of mmWave's major advantages is its privacy-preserving nature." Ha, haha, hahaha! It can measure your breathing, heart signature, gait, etc. With machine learning this data will certainly be enough to identify you.

I want to get off Mr Bone's Wild Ride.

Re: mmWave radar, you won't see it coming

#23

Post by hornej »

chrismorgan wrote: post #15

A technical error in one of the diagrams: Hall effect sensors are not binary, but one-dimensional, and are used so; their output voltage is directly proportional to the magnetic field strength. As for PIR sensors, fundamentally they’re certainly not binary, but I have no idea if they perhaps expose only a binary signal. A better example of a binary sensor might be an on/off switch.

most hall effect sensor applications i've seen use a schmitt trigger and output a digital (on/off) signal

Re: mmWave radar, you won't see it coming

#24

Post by mycall »

jasondclinton wrote: post #19

I've been waiting for someone to finally make a consumer stud finder that works and this just might finally happen after this deregulation of the spectrum. The construction industry would hand over wheelbarrows full of money for a BLE phone-paired puck that located studs and pipes behind drywall. Someone could even sell a "pro" version that combined the data from multiple pucks to render a 3D point cloud of the insid…

Would this be it?

https://blog.vayyar.com/walabot-diy-2-launch

Re: mmWave radar, you won't see it coming

#25

Post by mycall »

chrismorgan wrote: post #15

A technical error in one of the diagrams: Hall effect sensors are not binary, but one-dimensional, and are used so; their output voltage is directly proportional to the magnetic field strength. As for PIR sensors, fundamentally they’re certainly not binary, but I have no idea if they perhaps expose only a binary signal. A better example of a binary sensor might be an on/off switch.

If you include time dimension, hall effect sensors are two dimensional.

Re: mmWave radar, you won't see it coming

#26

Post by jcims »

krasin wrote: post #5
idontwantthis wrote: post #3

> Because mmWave radar doesn’t process visual light, what it sees is not personally identifiable. This makes it an ideal choice for monitoring where a camera would not be appropriate. Is 5mm resolution not enough to identify a face? What’s the difference between a 3d model of a person constructed from high res radar and a black and white photo? The radar sounds even more identifiable. Edit: Couldn’t you construct a m…

I worked with mmWave radars previously, but not professionally. In my opinion, it would be quite challenging to extract enough features from the current generation of mmWave radars, such as TI IWR1642 ([1]) which have around 4 receivers and 2-3 transmitters, because the incoming data, while having a lot of temporal resolution is very limited in spatial resolution. With greater number of antennas something like what y…

To an extent, but depending on the sampling rate and frequency and your ability to control the area being observed, there is still a lot of information available for modeling and biometric identification. In the extreme you can detect things like heartbeat, rate of breathing, etc.

For example, I have a CDM324 24Ghz radar module here on my desk. I set it up to 'watch' me type this comment from across the keyboard. This is an extremely simple module that I have powered by a bench power supply and the IF routed directly to the audio input on my desktop. It was sampled with audacity and amplified a bit to help with visibility. Towards the end of the recording I'm expecting a flat spot followed by regular motion followed by 'noise' as I pause motionless for ~10 seconds or so, then take about 5-6 exaggerated breaths, then resume typing.

This is with zero design, the wrong frequency for the job, and next to zero signal conditioning.

(post: i've included a zoomed in image of the 'motion demonstration' to show still/breathing/typing, then zoomed in on typing to show the detail, then a spectrogram and waveform of me reaching up to scratch my ear.)

https://imgur.com/a/0JmENYu

Bonus: yo check out my soundcloud - This is what the doppler signal actually sounds like:

Scratching my ear - https://soundcloud.com/buckrunner2/scratch

Talking directly at the module - https://soundcloud.com/buckrunner2/talking

Re: mmWave radar, you won't see it coming

#27

Post by acmegeek »

jasondclinton wrote: post #19

I've been waiting for someone to finally make a consumer stud finder that works and this just might finally happen after this deregulation of the spectrum. The construction industry would hand over wheelbarrows full of money for a BLE phone-paired puck that located studs and pipes behind drywall. Someone could even sell a "pro" version that combined the data from multiple pucks to render a 3D point cloud of the insid…

Would the Walabot fit the bill for you? I bought one when it first came out and seemed pretty good. I haven't messed with it in a couple years though.

https://walabot.com/see-through-walls

This seems like a pretty good review:

https://www.bobvila.com/articles/walabot-stud-finder/

Re: mmWave radar, you won't see it coming

#28

Post by neurodyne »

mycall wrote: post #24
jasondclinton wrote: post #19

I've been waiting for someone to finally make a consumer stud finder that works and this just might finally happen after this deregulation of the spectrum. The construction industry would hand over wheelbarrows full of money for a BLE phone-paired puck that located studs and pipes behind drywall. Someone could even sell a "pro" version that combined the data from multiple pucks to render a 3D point cloud of the insid…

Would this be it? https://blog.vayyar.com/walabot-diy-2-launch

They also seem to have development hardware available https://walabot.com/makers

Re: mmWave radar, you won't see it coming

#29

Post by choonway »

chrismorgan wrote: post #15

A technical error in one of the diagrams: Hall effect sensors are not binary, but one-dimensional, and are used so; their output voltage is directly proportional to the magnetic field strength. As for PIR sensors, fundamentally they’re certainly not binary, but I have no idea if they perhaps expose only a binary signal. A better example of a binary sensor might be an on/off switch.

the only true binary sensor i can think of are good old fashioned mechanical switches.

Re: mmWave radar, you won't see it coming

#30

Post by cj »

wavesquid wrote: post #9
idontwantthis wrote: post #3

> Because mmWave radar doesn’t process visual light, what it sees is not personally identifiable. This makes it an ideal choice for monitoring where a camera would not be appropriate. Is 5mm resolution not enough to identify a face? What’s the difference between a 3d model of a person constructed from high res radar and a black and white photo? The radar sounds even more identifiable. Edit: Couldn’t you construct a m…

You don't need to identify a face; you can identify people by Gait. If you can resolve something as big as a leg you've got enough, as long as you have it over 10 seconds or so.

(Genuinely curious) how do you know this?
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